Sky at Night - April 2014

create a stunning moon mosaic image

Sky at Night the biggest name in astronomy

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see mars at its brightest and best



Discover why this once wet world is  see mars at its now a desert 

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 Discover why this life in low once wet world is earth orbit now a desert

The challenges of living and working on the ISS

life in low earth orbit The challenges of living and working on the ISS

solar system hotspot

New insights into the volcanic moon Io

also in this issue also in scope test

preserving the night

with automatic guiding built in scope test

New insights into the volcanic moon Io solar system hotspot

preserving the night

this issue The UK’s newest Dark Sky areas uncovered Meade’s new LX600 telescope

The UK’s newest Dark Sky areas uncovered

Meade’s new LX600 telescope with automatic guiding built in

light unlocked The new instruments that will

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steady on

steady on Expert techniques to hold Expert techniques to hold higher binoculars binoculars higher for longer aPriL 2014 #107

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aPriL 2014 #107

www.skyatnightmagazine.com www.skyatnightmagazine.com

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Letter from the editor APRIL 03

this month’s contributors include... sean Blair

Welcome

Everything you need to know about Mars’s opposition

sPace writer

From Mariner 4’s from the editor APRIL 03 frst visitLetter in 1964 to HoW to contact us Curiosity’s presentSubscriptions, binders, CD cases and back issues 0844 844 0254 day explorations, Mon to Fri 8am to 8pm; Sat 9am to 1pm for orders Mars is the most Editorial enquiries visited destination for 0117 314 7411 space probes. Now two 9.30am to 5.30pm, Mon to Fri include... Advertising enquiries new spacecraft are on Will Gater 0117 314 8365 Everything you need to know about Mars’s opposition sean Blair their way to the Red astronomy author sPace writer Subscription email enquiries Planet From Mariner 4’s to uncover SeanWill marks [email protected] frst visit in 1964 to tackles thea invention more about its atmosphere. The data NASA’s HoW to contact usenquiries Editorial planetary Curiosity’s presentof the Subscriptions, binders, CD cases and back issues [email protected] MAVEN and India’s Mars Orbiter Mission  0844 844 0254 App enquiries murder explorations, spectroscope will send backday is set to give us new insights mystery: Mon to Fri 8am to 8pm; Sat 9am to 1pm for orders Mars is the most http://apps.immediate.co.uk/support what happened towith the a look Editorial enquiries into the planet’s protective envelope, why it visited destination for [email protected] at how its atmosphere of modern-day the 0117 314 7411 disappeared and the impact this had on the space probes. Now two 9.30am to 5.30pm, Mon to Fri Red Planet? Pagecontinue 34 equivalents to Editorial enquiries Advertising enquiries new spacecraft are on planet’s potentially life-sustaining supply of aid astronomers. Page 73 BBC Sky at Night Magazine, Immediate Media Co Will Gater 0117 314 8365 their way to the Red 34. Bristol Ltd, Tower House, Fairfax Street, Bristol, BS1 3BN astronomy author water. Find out more on page Subscription email enquiries Martin Planet to uncover WillleWis marks  [email protected] Though Mars’sThe dust storms Planetary imager more about the invention its atmosphere. data NASA’sand carbon Editorial enquiries dioxide ice Mars are visible a telescope, [email protected] its of theMartin MAVEN and India’s Orbiterwith Mission how to capture the images, then process spectroscope App enquiries explains will send back is set to give us new insights tenuous atmosphere is one thing you won’t and stitch them together to create a fnal http://apps.immediate.co.uk/support with a look how to into thesee, planet’s envelope, it [email protected] evenprotective with the planetwhy at its this at how its modern-day masterpiece rich in detail. And on page 73, make and the impact this had on the equivalents continue to thedisappeared Editorial month. April’s opposition is a great time to enquiries there’s the fascinating tale of one of astronomy’s most73of the planet’s potentially life-sustaining supply of aid astronomers. Page BBC Sky at Night Magazine, Immediate Media Co see the raft of details visible on the planet. Bristol Ltd, Tower House, Street, Bristol, BS1–3BN mostFairfax unsung tools the spectroscope. To tie water. Find out more on page 34. Red Planet its brightest Martin leWis From the dark markings that break up Mars’s Though Mars’s dust storms and carbon and best for the current in with the 200th anniversary of its invention, Planetary imager ice are visible withto a telescope, its polar how Martin apparition. Page 41 dioxidered-hued globe the white caps,to capture thewe images, process look then at how this instrument continues to explains tenuousMartin atmosphere is one thing you won’t and stitch them together to create a fnal Lewis’s feature on page 41 shows you unlock the secrets of starlight. how tonkin to stepHen see, even with the planet at its brightest this masterpiece rich in detail. And on page 73, how to get the most out of observing and make the theofissue! Binocular oBserver month. April’s opposition is a great time to there’s the fascinatingEnjoy tale of one astronomy’s most of the imaging thevisible Red on Planet this apparition. Stephen see the raft of details the planet. most unsung tools – the spectroscope. To tie Red Planet its brightest dispensesFrom the You’ll also fndthat expert on imaging dark markings breakadvice up Mars’s and best for the current in with the 200th anniversary of its invention, apparition. Page his 41 top tips red-hued globe to the white polar caps, Mars on page 64, and on page 93, we Carol look at how this instrument continues to on how to MartinLakomiak Lewis’s feature on page how 41 shows you unlock the secrets of starlight. stepHen tonkin explains to sketch the planet. get steadier how to get the most out of observing and Enjoy the issue! Binocular oBserver Elsewhere on page 80 you’ll views when observingimaging the Red Planetthis this month, apparition. Stephen Chris Bramley editor fndfnd a detailed guide to creating a lunar dispensesin thisYou’ll also expert advice on imaging with binoculars his topto. tipsPageMars page 64, Pete and on page 93, Carol month’s How 90 onmosaic. ps Next issue goes on sale 17 April. Lawrence takes you through Sean tackles a planetary murder mystery: what happened to the this month’s atmosphere of the contributors Red Planet? Page 34



Welcome





on how to get steadier views when observing with binoculars in this month’s How to. Page 90

Lakomiak explains how to sketch the planet. Elsewhere this month, on page 80 you’ll fnd a detailed guide to creating a lunar mosaic. Pete Lawrence takes you through

Chris Bramley editor

sky at night lots of ways to enjoy the night sky... ps Next issue goes on sale 17 April.

sky at night lots of ways to enjoy the night sky... television

online

FaceBook

poDcast

Visit our website for Find out what The Sky All the details of our The BBC Sky at Night online FaceBook poDcast ipaD reviews, competitions, at Night team will be latest issue, plus news Magazine team discuss Visit our website for Find out what The Sky All the details of our The BBC Sky at Night Get each month’s exploring in this from anddiscuss the latest news reviews, astrophotos, competitions, observing at Night team will be month’s latest issue, plus newsthe magazine Magazine team issue astro on your iPad,in observing exploring in this the magazine and tothe now withpodcast bonus video latest astro newsour in monthly guides and ourfrom forum episode onmonth’s page 19astrophotos, updates our website

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skyatnightmagazine.com 2014


04

In the magazine On the cOver 34

41

80

New to astroNomy? See The guide on page 88 and our online glossary at www.skyatnightmagazine.com/dictionary

mars at opposition

04

In the magazine On 114 the cOver 34

80

41

New to astroNomy? See The guide on page 88 and our online glossary at www.skyatnightmagazine.com/dictionary

mars at opposition

16

102

66 114 16

51

66

98 73

80

102

mosaicing the moon First Light

regulars

88 Skills

11 Bulletin mosaicing the moon 19 What’s on

on 73 the sky 90 5106 Eye 98 Stunning new images of space.

80

34 Mars’s missing features atmosphere 06 Eye on the sky

regulars 21 A passion for space

cover: thinkstock. nasa, this page: damian peach, pete lawrence, www.thesecretstudio.net

cover: thinkstock. nasa, this page: damian peach, pete lawrence, www.thesecretstudio.net

features

90

First Light

88 The guide The Local Group of galaxies.

88 Skills

90 How to Get steadier binocular views.

93 Sketching

88 The guide 11 Bulletin Mars at opposition. Sky at Night presenter Maggie Local Group of galaxies. The greatest whodunnit NEW Aderin-PocockThetells Stunning new images of space. of them all: we explore us to what 90 How 95 Scope Doctor 19 What’s on the mystery of the disappearing atmosphere. we can learn from the sounds of space. Get steadier binocular views. 34 Mars’s missing for space 93 Sketching 97 Reviews 41atmosphere Mars at opposition 21 A passion Sky at Night presenter Maggie Mars at opposition.

23 Jon Culshaw

TheThe greatest whodunnit of to them all: we explore ultimate guide viewing and imagingNEW First Light Aderin-Pocock tells us what 95 Scope Doctor thethe mystery of the disappearing atmosphere. Jon’stheoff-world travelogue continues. Red Planet as it comes to opposition. we can learn from sounds of space. 98 Meade LX600-ACF

97 Reviews

41 Mars at opposition

23 Jon Culshaw Dark recognised The66 ultimate guide toskies viewing and imaging 24 sUBscriBe First Light two more UK to sites gained Dark Sky status. Jon’s off-worldget travelogue theHow Red Planet as it comes opposition. your continues. issues at

6673Dark skies recognised Unlocking the

How two more UK sites gained Dark Sky status.

secrets of light

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Tried & Tested 24 sUBscriBe 102 26 Interactive 102 William Optics GTF get your issues at a discount

73How Unlocking 28 Hotshots the humblethe spectroscope will lead the26 Interactive James secrets of lightinto a new era of astronomy. Webb Space Telescope 28 Hotshots How the humble spectroscope will lead the James

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Tried & Tested 110 Books 106 QSI 683 WSG-8 CCD camera. 110 Books 112 Gear

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51 the sky iN 114 What I really 80 Mosaicing the Moon 51 the sky iN aPriL you need to know create your frst lunar 114 What I really 80AllMosaicing thetoMoon want to know is… Your 15-page guide to the aPriL image acquisition to completion. Allmosaic, you need from to know to create your frst lunar Webb Space Telescope into a new era of astronomy.

mosaic, from image acquisition to completion.



want to know is…

What is life like on the ISS? Your 15-page guide to the night sky featuring the top What is life like on the ISS? night sky featuring the topan all-sky chart, a sights, sights, an all-sky chart, a deep-sky tour and more… deep-sky tour and more…

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this app features:  3D views of legendary spacecraft, allowing you to examine them from different angles  themed photo galleries featuring amazing images  historic video footage  interactive diagrams  360º panoramic views of the moon  a foreword by sir patrick moore

aVaiLaBLe noW on itUnes – onLy £3.99 aVaiLaBLe noW on itUnes – onLy £3.99 todownload download www.skyatnightmagazine.com/man-in-space-ipad-app to visit visit www.skyatnightmagazine.com/man-in-space-ipad-app skyatnightmagazine.com 2012 skyatnightmagazine.com 2012

Asteroids

amass Asteroids amass

Against gas clouds and star clusters, an armada of space rocks sails silently through the darkness WIdE-fIEld INfrArEd SurvEy ExplOrEr, 23 JANuAry 2014

There are more than 100 asteroids visible in 2158 to the centre right, this star feld is home this image from NASA’s Wide-feld Infrared to vast, billowing clouds of gas and dust Survey Explorer (WISE). Although it is not revealed in infrared light. easy to spot them all, some do stand out as The data used to create this image was a series of dots – like asteroid (2415) Ganesa, captured during WISE’s primary all-sky survey. which can be seen just left of centre. The spacecraft went into hibernation shortly The asteroids, located within our Solar afterwards in 2011 but was revived last year, WIdE-fIEld SurvEy ExplOrEr, 23of JANuAry 2014 renamed NEOWISE and commissioned to hunt System, INfrArEd sit against an infrared view a background star feld around 30inlightyears down more There are more than 100 asteroids visible 2158 to the centre right, this of starthe feldelusive is homespace rocks captured Along withWide-feld bright clusters, so brilliantly inand thisdust image. thisacross. image from NASA’s Infrared like NGC to vast, billowing clouds of gas

Against gas clouds and star clusters, an armada of space rocks sails silently through the darkness

Survey Explorer (WISE). Although it is not easy to spot them all, some do stand out as a series of dots – like asteroid (2415) Ganesa, which can be seen just left of centre. The asteroids, located within our Solar System, sit against an infrared view of a background star feld around 30 lightyears across. Along with bright clusters, like NGC

revealed in infrared light. The data used to create this image was captured during WISE’s primary all-sky survey. The spacecraft went into hibernation shortly afterwards in 2011 but was revived last year, renamed NEOWISE and commissioned to hunt down more of the elusive space rocks captured so brilliantly in this image.

NASA/JPL-CALteCh/UCLA

NASA/JPL-CALteCh/UCLA

 Engaging rings

▲ A grand spiral in the southern sky HubblE SpACE ▲TElESCOpE A grand spiral in the2014 9 JANuAry southern sky This image of

HubblE SpACE M83, the Southern TElESCOpE pinwheel2014 galaxy, 9 JANuAry

shows off a beautiful

This imageof of vivid hues. range M83, the Southern The reason for such pinwheel galaxy, vibrancy: a vast shows off a beautiful number ofhues. stars in range of vivid Thethe reason for such throngs of birth vibrancy: a vast M83 is and death. number of stars in a barred spiral, the the throngs of birth same and death.type M83of is galaxy as thespiral, MilkytheWay, a barred same of galaxy buttype unlike our home as the Milky Way, in space it has a but unlike our home ‘double nucleus’ in space it has a at itsnucleus’ heart. ‘double at its heart.



 Engaging rings CASSINI SpACECrAfT 20 JANuAry 2014 Saturn’s famous ring system takes centre stage in this infrared image from Cassini. Taken from a distance of 1.1 million km, it reveals a bright spot in the rings – look for it just left of centre – called an opposition surge. This occurs when the Sun is directly behind the probe. Astronomers will analyse the size and magnitude of the surge to learn more about the properties of the ring particles.

CASSINI SpACECrAfT 20 JANuAry 2014 Saturn’s famous ring system takes centre stage in this infrared image from Cassini. Taken from a distance of 1.1 million km, it reveals a bright spot in the rings – look for it just left of centre – called an opposition surge. This occurs when the Sun is directly behind the probe. Astronomers will analyse the size and magnitude of the surge to learn more about the properties of the ring particles.

eye on the sky APRIL 09

 Rose tinted gasses EurOpEAN SOuTHErN ObSErvATOry, 22 JANuAry 2014 ESO’s very large Telescope captured the lagoon Nebula in exquisite, pale pink detail in this stunning new image. The nebula, a vast stellar factory where new stars are born, spans almost 100 lightyears in diameter, and lies between 4,000 and 6,000 lightyears from Earth.

eye on the sky APRIL 09

 Rose tinted gasses EurOpEAN SOuTHErN ObSErvATOry, 22 JANuAry 2014 ESO’s very large Telescope captured the lagoon Nebula in exquisite, pale pink detail in this stunning new image. The nebula, a vast stellar factory where new stars are born, spans almost 100 lightyears in diameter, and lies between 4,000 and 6,000 lightyears from Earth.

 The leftover lake MArS ExprESS SpACECrAfT, 12 dECEMbEr 2013



Giant mounds of layered deposits sit surrounded by soft sand and dust in Mars’s Juventae Chasma. New observations like the one from ESA’s Mars Express indicate that running water may have been responsible for moulding these mounds – scientists believe the numerous layers were mainly The leftover lakebuilt up from lake deposits.

MArS ExprESS SpACECrAfT, 12 dECEMbEr 2013



SCieNCe iNStitUte, eSO/VPhAS+ teAm, eSA/dLr/FU berLiN (g. NeUkUm)

NASA/eSA ANd the hUbbLe heritAge teAm (StSCi/AUrA), NASA/JPL-CALteCh/SPACe

SCieNCe iNStitUte, eSO/VPhAS+ teAm, eSA/dLr/FU berLiN (g. NeUkUm)

NASA/eSA ANd the hUbbLe heritAge teAm (StSCi/AUrA), NASA/JPL-CALteCh/SPACe

Giant mounds of layered deposits sit surrounded by soft sand and dust in Mars’s Juventae Chasma. New observations like the one from ESA’s Mars Express indicate that running water may have been responsible for moulding these mounds – scientists believe the numerous layers were mainly built up from lake deposits.

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Bulletin APRIL 11

Bulletin The latest astronomy and space news written by Hazel Muir Circumbinary planets are rare, with only a handful found so far

Bulletin The latest astronomy and space news written by Hazel Muir

plUs

CUttInG 14 CHris LintOtt 16 Lewis DartneLL

Our experts examine the hottest new astronomy research papers Bulletin APRIL 11

plUs

CUttInG 14 CHris LintOtt 16 Lewis DartneLL

eDGe

Our experts examine the hottest new astronomy research papers

Comment

Circumbinary planets are rare, with only a handful found so far

by Chris Lintott

Comment by Chris Lintott

The key to understanding this bizarre new system is that it orbits not one, but two stars – one of a handful of ‘circumbinary’ planets known. Since the discovery of the frst such world, a hardy group of theorists and computer modellers have been trying to fgure out the rules that dictate how such planets might form. Their results suggested that the gravitational pull of the binary star would wrench any protoplanetary disc and hence any subsequent planets into alignment. telescope Science institute (StSci)That in Maryland. NASA ScieNtiStS hAve discovered a strange process clearly “After that, we saw five more transits a row.” world that wobbles wildly on its axis, much like wasn’tin effective here, leaving Kepler-413b º the planet’s orbit is tilted by 2.5 in relation on a child’s spinning top. its tilt may change by as an orbit that only sometimes to the orbit of the binary stellar pair; these much as 30 º over 11 years, resulting in extreme produces transits. Its telescope Science institute (StSci) in Maryland. NASA ScieNtiStS hAve discovered a strange inclination is only a observations suggest that the planet’s orbit and rapid climate changes. “After that, we saw five more transits in a row.” world that wobbles wildly on its axis, much like coupleoften of degrees – not wobbles too, so much that the planet the planet, a gas giant known as Kepler-413b, the planet’s orbit is tilted by 2.5º in relation a child’s spinning top. its tilt may change by as unprecedented, but enough to pass in pair; frontthese of the stars from is about 65 times as resulting massiveinasextreme earth andtosits the in orbit of fails the binary stellar much as 30 º over 11 years, in this our case to make a big observations that theon planet’s orbit andthe rapid climate changes. difference to what we perspective earth. constellation of cygnus. it orbits a close pair suggest see. With planets around wobbles that the planet the planet, stars a gas giant known as Kepler-413b, intriguingly, theoften finding may also mean that of dwarf every 66 days, causing them to too, so much binary stars already fails to pass in front of the stars from our is about 65 times as massive as earth and sits in many transiting planets may go undetected dim slightly as it passes in front. this should proving much more common the constellation of cygnus. it orbits a close pair perspective on earth. than anyone would have because their transits are rare. “Presumably happen like clockwork but – as the Kepler space intriguingly, the finding may also mean that of dwarf stars every 66 days, causing them to suspected a few years there are planets out there like this one that telescope revealed – the gas giant’s transits are many transiting planets may go undetected dim slightly as it passes in front. this should ago, this window onto because their transits are rare. “Presumably happen like clockwork but – as the Kepler space we’re not seeing because we’re in what the we might be missing unusually irregular. there are planets out there like this one that telescope revealed – the gas giant’s transits are is hugely signifcant. unfavourable period,” says Peter Mccullough, “Looking at the Kepler data over the course of

Wobbly planetcircles

double star

Wobbly planetcircles

double star

Is this the frst member of a ‘silent majority’ of unseen planets?

NASA/JPL-CALteCh

Is this the frst member of a ‘silent majority’ of unseen planets?

NASA/JPL-CALteCh

eDGe

The key to understanding this bizarre new system is that it orbits not one, but two stars – one of a handful of ‘circumbinary’ planets known. Since the discovery of the frst such world, a hardy group of theorists and computer modellers have been trying to fgure out the rules that dictate how such planets might form. Their results suggested that the gravitational pull of the binary star would wrench any protoplanetary disc and hence any subsequent planets into alignment. That process clearly wasn’t effective here, leaving Kepler-413b on an orbit that only sometimes produces transits. Its inclination is only a couple of degrees – not unprecedented, but enough in this case to make a big difference to what we see. With planets around binary stars already proving much more common than anyone would have suspected a few years ago, this window onto what we might be missing is hugely signifcant. ChrIS LInToTT co-presents

we’re not seeing because we’re in the unusually irregular. The Sky at Night also from “is there a silentChrIS majority 1,500 days, saw data three transits in of the first 180 unfavourable period,” saysStSci. Peter Mccullough, “Looking at thewe Kepler over the course LInToTT co-presents that seeing?” days, then we three had 800 daysinwith no180 transits atfrom all,”StSci. The Sky at Night also “iswe’re there anot silent majority 1,500 days, we saw transits the first we’re not > seeing?” days, then we had 800 days with noKostov transits from at all,” thethat See Comment, right says team leader veselin Space > See Comment, right says team leader veselin Kostov from the Space



12

news in

brief

ngC 6946 and its companions appear to be linked by a trail of diffuse hydrogen, shown in red

Odyssey gets a new quest

NASA is gradually altering the orbit of its Mars Odyssey spacecraft 12 to allow the probe to view the planet’s surface in morning daylight. It ngC 6946 and its will reach its intended companions appear to be linked by a trail of diffuse new orbit in November hydrogen, shown in red 2015 and make the frst systematic observations of Odyssey getsfogs, clouds how morning a and new quest surface frost develop. NASA is gradually Its measurements could altering the orbit of its help demystify temperatureMars Odyssey spacecraft driven processes, such as to allow the probe to view the planet’s surface fows forming on slopes in morning daylight. It during warm seasons. will reach its intended “We’re teaching an old new orbit in November spacecraft tricks,” 2015 and make new the frst systematic observations of says Jeffrey Plaut from how morning fogs, clouds NASA’s Jet Propulsion and surface frost develop. Laboratory in California. Its measurements could “Odyssey will be in position help demystify temperatureto see Mars in a as different driven processes, such fows forming slopes light than on ever before.”

news in

coLoRADo/ceNtRAL ARizoNA coLLege AND NASA/eSA/UNiVeRSity oF LeiceSteR AND NASA/JPL-cALtech/UNiVeRSity oF ARizoNA/LANcASteR UNiVeRSity

NASA/JPL, D.J. PiSANo (WVU) B. SAxtoN (NRAo/AUi/NSF) PALomAR oBSeRVAtoRy – SPAce teLeScoPe ScieNce iNStitUte 2ND DigitAL Sky SURVey (cALtech) NASA/JPL, D.J.RADio PiSANo (WVU) JAxA, B. SAxtoN (NRAo/AUi/NSF) PALomAR – SPAce teLeScoPe ScieNce iNStitUte 2ND DigitAL Sky SURVey (cALtech) WeSteRBoRk SyNtheSiS teLeScoPe, NASA/eSA/S. toFt (NieLS BohR iNStitUte)oBSeRVAtoRy AND A. FeiLD (StSci), NASA/JPL-cALtech/UNiVeRSity oF WeSteRBoRk SyNtheSiS RADio JAxA, NASA/eSA/S. toFt (NieLS BohR iNStitUte) AND A. FeiLD (StSci), NASA/JPL-cALtech/UNiVeRSity oF coLoRADo/ceNtRAL ARizoNA coLLege AND teLeScoPe, NASA/eSA/UNiVeRSity oF LeiceSteR AND NASA/JPL-cALtech/UNiVeRSity oF ARizoNA/LANcASteR UNiVeRSity

brief

during warm seasons. “We’re teaching an old spacecraft new tricks,” says Jeffrey Plaut from NASA’s Jet Propulsion Laboratory in California. “Odyssey will be in position to see Mars in a different light than ever before.”

Rivers of hydrogen fuel galaxies

Rivers of hydrogen fuel galaxies

Newly discovered gas streams may explain vigorous star formation

extreme blaCk hOle disCOvered

An intriguing river of hydrogen fowing effectively siphoning cold gas away from through space has been spotted by a radio their smaller neighbours. the cold gas then A black hole in an telescope in West virginia. Astronomers say becomes fuel for new stars. “But this tenuous elliptical galaxy about such flaments, never seen before because they hydrogen has been simply too diffuse to 3.9 billion lightyears Newly discovered gas streams may explain vigorous star formation away may be the most are so faint, could explain how some spiral detect, until now,” says Pisano. extreme blaCk An intriguing river of hydrogen fowing effectively siphoning cold from powerful ever found. galaxies manage to maintain constant, vigorous He gas hasaway discovered one of the hypothesised hOle disCOvered through space has been spotted by a radio their smaller neighbours. the cold gas thenafter studying a galaxy called Julie Hlavacek-Larrondo A black hole in an star formation. rivers of hydrogen in West virginia. Astronomers say becomes fuel for new stars. “But this tenuous elliptical galaxy about from Stanford University telescope in Spiral galaxies likebecause our own Milky Way ngC 6946. this galaxy lies about 22 million such flaments, never seen before they hydrogen has been simply too diffuse to 3.9California billion lightyears and colleagues typically have rather tranquil, but steady, lightyears away may be the most are so faint, could explain how some spiral detect, until now,” says Pisano. away on the border of the Cepheus made the discovery using powerful ever found. galaxies manage to maintainBut constant, vigorous discoveredand one of the hypothesised star formation. the star formationHeinhas some Cygnus. Observations using the 100m green NASA’s Chandra X-ray Julie Hlavacek-Larrondo star formation. rivers of hydrogen after studying a galaxy called the faint glow of a others is more lively. these galaxies often Bank telescope revealed Observatory and other from Stanford University in Spiral galaxies like our own Milky Way ngC 6946. this galaxy lies about 22 million warm shrouds of hydrogen gas, but neutral hydrogen stream connecting ngC 6946 California and colleagues telescopes. They estimatetypicallyhave have rather tranquil, but steady, lightyears away on the border of the Cepheus made the discovery using astronomers suspected they must also have with neighbouring galaxies, suggesting it does that the black hole is star formation. But the star formation in some and Cygnus. Observations using the 100m green NASA’s Chandra X-ray to explain theBank high indeed hydrogen off its smaller neighbours. about a thousand trillionothers is cold more hydrogen lively. theseinfows galaxies often telescope revealed thesiphon faint glow of a Observatory and other have warm shrouds of hydrogen gas, but neutral hydrogen stream connecting ngC 6946 times as massive as the star-formation rates. An alternative possibility is that the cold telescopes. They estimate astronomers suspected they must also have with neighbouring galaxies, suggesting it does thatSun. the black hole is jets Energetic “We knew that the fuel for star formation had hydrogen stream exists because ngC 6946 had cold hydrogen infows to explain the high indeed siphon hydrogen off its smaller neighbours. about a thousand sprouting outtrillion from it seem to come from somewhere,” says Daniel Pisano a close encounter with another galaxy in the times as massive as the star-formation rates. An alternative possibility is that the cold to have created two large from West virginia in Morgantown. distant past. this could have left a Sun. Energetic jets “We knew that the fuel for star university formation had hydrogen stream exists because ngC 6946interaction had cavities, wide sprouting out each from it as seem “So far, however, we’ve detected only about 10 ribbon of neutral atomic hydrogen in its wake. to come from somewhere,” says Daniel Pisano a close encounter with another galaxy in the as our Milkytwo Way, to have created large from West virginia university in Morgantown. distant past. this interaction could have left a per cent of what would be necessary to explain if that were the case, however, astronomers cavities, eachcurtailing as wide severely “So far, however, we’ve detected only about 10 ribbon of neutral atomic hydrogen in its wake. what we observe in many galaxies.” would expect to see a small but observable as star our Milky Way, formation. per cent of what would be necessary to explain if that were the case, however, astronomers severely curtailing One leading theory is that rivers of gas, of stars in the flament, which what we observe in many galaxies.” would expect to see population a small but observable star formation. known as cold fows, throughof stars in have not beenwhich detected. One leading theory is that riversferry of gas,hydrogenpopulation the flament, known asintergalactic cold fows, ferry hydrogen through have not been detected. space, with large galaxies www.gb.nrao.edu intergalactic space, with large galaxies



www.gb.nrao.edu

Bulletin APRIL 13

news in

Asteroid’s odd interior revealed

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The density of a space rock can be extremely variable

a telescope at the La silla observatory in chile. their measurements of its spin rate combined with theoretical models hint that itokawa has two distinct densities. one possibility for this could Bulletin APRIL 13 be that it formed from two rocks that merged. “this is the frst time we have ever been able to determine what it is like inside an asteroid,” says Lowry, who calls it “a signifcant step” forward. www.eso.org/lasilla

asteRoids can Have a highly varied internal structure, scientists say. observations of peanutshaped near-earth asteroid 25143 itokawa suggest that its density is more than 60 per cent higher on one side than it is on the other. it’s the frst time that such a difference has been found. stephen Lowry from the university of Kent and colleagues studied the space rock – visited by the Japanese spacecraft Hayabusa in 2005 – using

Asteroid’s odd interior revealed The density of a space rock can be extremely variable the two parts of

1,750kg/m3

a telescope at the La silla observatory in chile. their measurements of its spin rate combined with theoretical models hint that itokawa has two distinct densities. one possibility for this could be that it formed from two rocks that merged. “this is the frst time we have ever been able to determine what it is like inside an asteroid,” says Lowry, who calls it “a signifcant step” forward. www.eso.org/lasilla

asteRoids Have a highly varied internal asteroidcan itokawa structure, scientists say. observations of peanuthave markedly shaped near-earth asteroid different densities 25143 itokawa suggest that its density is more than 60 per cent higher on one side than it is on the other. it’s the frst3time 2,850kg/m that such a difference has been found. stephen Lowry from the university of Kent and colleagues studied the space rock – visited by the Japanese spacecraft Hayabusa in 2005 – using the two parts of asteroid itokawa have markedly different densities

1,750kg/m3

Using images from Hubble and NASA’s Cassini spacecraft from April and May 2013, astronomers have compiled a movie of aurorae at Saturn’s poles. It should clarify how the giant planet’s polar light shows evolve following saturn’s aurOrae solar outbursts. in Full glOry “In 2013, we were Using images from treated to a veritable Hubble and NASA’s smorgasbord of dancing Cassini spacecraft from aurorae, from steadily April and May 2013, astronomers have shining rings to super-fast compiled a movie of bursts of light shooting aurorae at Saturn’s poles. across the pole,” says It should clarify how the Jonathan Nichols from the giant planet’s polar light shows evolve following University of Leicester, solar outbursts. who led the work on the “In 2013, we were Hubble images.

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treated to a veritable smorgasbord of dancing aurorae, from steadily shining rings to super-fast bursts of light shooting across the pole,” says Jonathan Nichols from the University of Leicester, who led the work on the Hubble images.

2,850kg/m3

nasa and FranCe plan mars prObe

gALACTIC fAMILy TrEES NO LONgEr A MySTEry

The US has teamed up with france to launch a lander to Mars in 2016. Space offcials from both nations have signed an agreement to join forces on the InSight mission, which will measure seismic activity on Mars and reveal structural details of its deep interior. “The research generated by this collaborative mission will give our agencies more information about the early formation of Mars, which will help us understand more about how Earth evolved,” says NASA administrator Charles Bolden.

RigoRous obseRvations by world-leading the study directly shows they’re descendants of telescopes, including Hubble and Herschel, have an earlier population of dusty ‘starburst’ galaxies unravelled the history of the most massive galaxies that voraciously used up available nasa gas forand star FranCe plan in the universe. the results show how early galaxies formation very quickly. gALACTIC fAMILy TrEES NO LONgEr A MySTEry mars prObe evolved via initial violent bursts of star formation “We at last show how these compact galaxies can The US has teamed up RigoRous obseRvations by world-leading the study directly shows they’re descendants of into extremely high-density galaxy cores, then form, how it happened and when itwith happened,” says france to launch telescopes, including to Hubble Herschel, have galaxies. an earlier population of dusty a lander to Mars in fnally collided formand giant elliptical sune toft from‘starburst’ the nielsgalaxies bohr institute in copenhagen, unravelled the history of the most massive galaxies that voraciously used up available gas for star 2016. Space offcials the timeline solves a decade-long mystery denmark, whose team confrmed from the both evolutionary nations have in the universe. the results show how early galaxies formation very quickly. about how compact elliptical galaxies that existed tree through detailed studies of many galaxies of signed an agreement evolved via initial violent bursts of star formation “We at last show how these compact galaxies can to join forces on the into extremely high-density galaxy form, how it happened and whenafter it happened,” says phase, the galaxies when the universe was onlycores, threethen billion years old different ages. the compact InSight mission, which fnally collided form giantofelliptical galaxies. the niels bohr institute in copenhagen, – less than to a quarter its current age – but sune had toft from grew slowly through mergers into will giant ellipticals. measure seismic the timeline solves a decade-long mystery denmark, whose team confrmed the evolutionary already completed most of their star formation. www.hubblesite.org activity on Mars and about how compact elliptical galaxies that existed when the universe was only three billion years old evolution ellipticals – lessthe than a quarterof of giant its current age – but had hascompleted been laidmost bareof their star formation. already

tOday

13.7 billion years 5 billion years tOday

local elliptical galaxy local elliptical galaxy

tree through detailed studies of many galaxies of reveal structural details different ages. after the compact phase, the galaxies of its deep interior. big grew slowly through mergers into giant ellipticals. “The research bang www.hubblesite.org generated 1 billion yearsby this

1.5 billion years big

the evolution of giant ellipticals has been laid bare

13.7 billion years 5 billion years

3 billion years

3 billion years

merging galaxies

merging galaxies

saturn’s aurOrae in Full glOry

Compact galaxy

2 billion years 1 billion years

bang

1.5 billion years

2 billion years

Compact quasar galaxy

quasar

dusty starburst galaxy

dusty starburst galaxy

merger

collaborative mission will give our agencies more information about the early formation of Mars, which will help us understand merger more about how Earth evolved,” says NASA administrator Charles Bolden.



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CUTTING our experts examine the hottest new research

wherever they occur, with some adjustment for factors such as the composition of the material. But not all Type Ia supernovae ft this pattern. Suggestions include exotic models of stellar evolution, interactions between two white dwarfs or even mergers in triple star systems. Whatever is going on, a growing body of evidence suggests an important role is played by so-called ‘prompt’ Type Ia supernovae, which occur less than 500 million years into a system’s lifetime. A new Hubble Space Telescope survey of 24 Type Ia supernovae sets out to understand how the of prompt wherever they occur,distribution with some adjustment for and standard supernovae factors such as the composition of the material. Buttime. Given that this has changed over cosmic not all Type Ia supernovae ft this pattern. Suggestions survey looks more than 10 billion years into the include exotic models of stellar evolution, interactions past, to a time when star formation was much more between two white dwarfs or even mergers in triple prevalent than it is today, star systems. Whatever is going on, a growing body we should expect the of progenitors capable of producing either of evidence suggests number an important role is played by so-called ‘prompt’ Type Ia supernovae, whichsupernovae occur prompt or standard to be different from less than 500 million years into a system’s lifetime. that in the local Universe. Previous surveys had A new Hubble Space Telescope survey of 24 Type thathow such Ia supernovae sets outsuggested to understand theanalysis would reveal that the

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The prompt supernovae

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Type Ia supernovae appear to be more varied then we originally thought

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our experts examine the hottest new research

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The prompt supernovae Type Ia supernovae appear to be more varied then we originally thought

distribution of prompt and standard supernovae has changed over cosmic time. Given that this survey looks more than 10 billion years into the past, to a time when star formation was much more prevalent than it is today, we should expect the number of progenitors capable of producing either prompt or standard supernovae to be different from that in the local Universe. Previous surveys had suggested that such analysis would reveal that the

“A growing body of evidence suggests an important role is played “A growing bodyby of prompt Ia supernovae” evidenceType suggests

M

distant included ost of the buzz surrounding the recent prompt variant might accountgalaxies for as many as half in the survey, which suggests prompt supernova 2014J in relatively local of all Type Ia supernovae. Giventhat the rising star-supernovae accounting for formation rate as we look back in time, that should half of all such events might be an overestimation. M82 is due2014J to itsexploded status inasM82, the 11.5 nearest the type ia supernova designated million lightyears mean plenty of supernovae for us to observe. from Earth. it was theType closestIa supernova of this typethan discovered in the past few decades The data favour a much lower fraction, perhaps as event in more a century. In fact, few supernovae were found in the most small as one in 20, albeit with small error bars. We normally hear about Type Ia supernovae when distant galaxies included in the survey, which ost of the buzz surrounding the recent Far fromaccounting understanding what prompt Type Ia they’re used to measure the expansion of the suggests that prompt supernovae for supernova 2014J in relatively local half of all such eventssupernovae might be an overestimation. M82 is dueeffects to its status as theenergy’, nearest but all of are, we’re still struggling to count them. Universe and the of ‘dark The data favour a much lower fraction, perhaps Type Ia event in more than a century. More observations will as help, and large Hubble surveys this cosmological excitement hides the embarrassing small as one in 20, albeit with small error bars. We normally hear about Type Ia supernovae when are already underway. Given M82’s status as a truth that these supernovae are poorly understood. Far from understanding what prompt Type Ia they’re used to measure the expansion of the star-forming system, though, and the The standard picture of a Type Ia supernova supernovae are, we’reprolifc still struggling to count them. Universe and the effects of ‘dark energy’, but all of chance that 2014J is asurveys prompt event, perhaps the depends on the transfer of the material between two More observations will help, and large Hubble this cosmological excitement hides embarrassing are already underway. Given M82’s status as a objects is to look closer to truth thatlocked these supernovae are poorly understood. best way to study these stars, in a mutual gravitational embrace in a prolifc star-forminghome, system, fun though, and the The standard picture of a Type Ia supernova though staring at the distant Universe is. binary system. If one of the stars is a white dwarf, chance that 2014J is a prompt event, perhaps the depends on the transfer of material between two and the two are close enough, then material will be best way to study these objects is to look closer to stars, locked in a mutual gravitational embrace in a pulled off the larger builddwarf, up on the home, fun though staring at the distant Universe is. binary system. If one of thestar starsand is a white Chris Lintott is an smaller Once enough hasbeaccreted, and the two one. are close enough, then material material will astrophysicist and pulled the larger star andignition build up becomes on the thenoffthermonuclear inevitable, Chris Lintott was reading… Type Ia Supernova Rate Chris Lintott is an co-presenter of The Sky smaller one. Once enough material has accreted, and we see a supernova. astrophysicist and Measurements to Redshift 2.5 from CANDELS: at Night on BBC TV. then thermonuclear ignition becomes inevitable, Chris Lintott was reading… Type Ia Supernova Rate co-presenter of The Sky This right – the need for a set amount of Searching for Prompt Explosions in the Early Universe and we see aseems supernova. He is also the director Measurements to Redshift 2.5 from CANDELS: at Night on BBC TV. material trigger ignition explains Ia by SteveninAtheRodney et al This seemsto right – the need for a set amount why of Type of the Zooniverse project. Searching for Prompt Explosions Early Universe He is also the director material to trigger ignition explains Typeluminosity Ia supernovae have roughly thewhy same it online at http://arxiv.org/abs/1401.7978 by Steven A Rodney etread al of the Zooniverse project.

NASA/ESA, A. GoobAr (Stockholm UNivErSity) ANd thE hUbblE hEritAGE tEAm (StSci/AUrA)

NASA/ESA, A. GoobAr (Stockholm UNivErSity) ANd thE hUbblE hEritAGE tEAm (StSci/AUrA)

an important role prompt variant might is account for as many as half of all Type Ia supernovae. Given the rising starplayed by prompt formation rate as we look back in time, that should the type ia supernova designated 2014J exploded in M82, 11.5 million lightyears mean plenty of supernovae for us to observe. from Earth. it was the closest supernova of this type discovered in the past few decades Type Ia supernovae” In fact, few supernovae were found in the most

M

supernovae have roughly the same luminosity



read it online at http://arxiv.org/abs/1401.7978

Bulletin APRIL 15

Mars gains a fresh crater

news in

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Spacecraft images reveal a spectacular new impact NASA’S MArS rEcONNAiSSANcE Orbiter has spotted a dramatic new crater on the red planet. the impact scar, which is around 30km wide, did not exist in images dating back to July 2010, APRIL 15 but turned up in shots taken inBulletin May 2012. After noticing the change, scientists used the orbiter’s HiriSE camera to take a closer look at the region in November 2013 – capturing the image shown on the left. it’s been estimated that more than 200 of the Spacecraft images reveal a spectacular new impact space rocks that hit Mars every year create craters at BroWn dWArf NASA’S MArSleast rEcONNAiSSANcE has impacts 3.9m wide, but Orbiter few of the striking hAslook redasskies spotted a dramatic new crater on the red planet. as this one, which is surrounded aUsing radial of theburst Very Large the impact scar, which is around 30km wide, telescope in Chile, debris that few out over a distance of about 15km. did not exist in images dating back to July 2010, astronomers have found a NASA launched the Mars but turned up in shots taken in May 2012. After reconnaissance nearby brown Orbiter dwarf star noticing the change, scientists used the orbiter’s with in curiously red2006. skies. in August 2005. it entered Mars’s orbit March The new crater is not really blue; this tint is a result of HiriSE camera to take a closer look at the Brown dwarfs are stars enhanced colourisation to remove reddish dust www.nasa.gov/mro

GAiA OPeNS itS eyeS

satellite galaxy of the Milky Way. “it provides just a tiny taste of the excellence and challenges ahead, to turn Gaia data into ESA’S GAiA understanding SpAcEcrAft hasof taken stunning human the aMilky Way’s testorigins,” image following its launch in December 2013. says Gaia scientist Gerry Gilmore from the shot, shown right, shows a dense cluster of the University of cambridge. “One substantial stars within the Large Magellanic cloud, a step galaxy for astronomy, satellite of the Milkyone Way.huge leap still to come.” Gaia will observe a stars around “it provides just a tiny tastebillion of the excellence and70 challenges ahead,year to turn data intoto build our times every in Gaia an attempt human of the Way’s Way. mostunderstanding accurate map of Milky the Milky origins,” says Gaia scientist Gerry Gilmore from http://sci.esa.int/gaia

GAiA OPeNS itS eyeS

the University of cambridge. “One substantial step for astronomy, one huge leap still to come.” Gaia will observe a billion stars around 70 times every year in an attempt to build our most accurate map of the Milky Way. http://sci.esa.int/gaia

news in

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unusually red atmosphere. “the thick clouds on this particular brown dwarf are mostly made of mineral dust,” says Marocco. the compounds include the magnesium-rich mineral enstatite and a crystalline form of aluminium oxide.

Mercury iMAGes MounT up

We’re unlikely to see many images like this from Gaia – its main role is that of a galactic cartographer

Looking back

We’re unlikely to see many images like this from Gaia – its main role is that of a galactic cartographer

Mercury iMAGes MounT up

NASA’s Messenger spacecraft, launched in 2004, has now returned more than 200,000 images of the planet Mercury – 200 times the number promised in the mission proposal. the probe willwe nowcan have across earth as they rotate, On 10 April 1983, The Sky at its orbit lowered so it observe regular pulses from them. Night broadcast discussed a can take high-resolution the discovery images of PSRofB1937+21 bizarre new sighting in the night the rocky extraordinary – how could a Astronomers across earth as theywas rotate, we can On 10 Aprilsky. 1983, The Sky at had discovered world’s surface. regular pulses from possibly them. Night broadcast discussed a as PSR observe pulsar spin that fast? a pulsar, known B1937+21, the discovery of PSR B1937+21 concluded that they bizarre newspinning sighting in642 the night Astronomers times a second. was extraordinary – how could a sky. Astronomers had discovered can be spun up to enormous speeds A pulsar is a neutron pulsar star, which possibly spin that fast? a pulsar, known as PSR B1937+21, when stars dump forms a massive star explodes Astronomers concluded thatcompanion they spinning 642 timeswhen a second. be spun A pulsar in is aaneutron star, which materialspeeds onto them, delivering supernova, leavingcan behind a up to enormous when companion stars dump momentum. the spin rate of forms whensuperdense a massive starcore explodes angular roughly 15km material onto them, delivering in a supernova, leaving behind a wide. Neutron stars can emit intense PSR B1937+21 has since been angular momentum. the spin rate of superdense core roughly 15km surpassed radiation poles, has since PSR B1937+21 been by only one other known wide. Neutron stars canfrom emit their intensemagnetic pulsar, 716 times a second. andtheir if their radiation sweep surpassed by only one other spinning known radiation from magnetic poles, beams pulsar, spinning 716 times a second. and if their radiation beams sweep

Looking backApril 1983 April 1983

As pulsars spin, their beams sweep s spin, their sarion puliat Asrad s mo cos eep thems sw ros aciati ons bea rad across the cosmos

NASA’s Messenger spacecraft, launched in 2004, has now returned more than 200,000 images of the planet Mercury – 200 times the number promised in the mission proposal. the probe will now have its orbit lowered so it can take high-resolution images of the rocky world’s surface.



NASA/JPL-CALteCh/UNiv. of ArizoNA, eSA/DPAC/AirbUS DS, NeiL J Cook, CeNter for AStroPhySiCS reSeArCh, UNiverSity of hertforDShire, NASA/JohNS hoPkiNS UNiverSity APPLieD PhySiCS LAborAtory/CArNegie iNStitUtioN of WAShiNgtoN

region in November 2013 – capturing the image shown on the left. it’s been estimated that more than 200 of the space rocks that hit Mars every year create craters at least 3.9m wide, but few of the impacts look as striking as this one, which is surrounded a radial burst of ESA’S GAiA SpAcEcrAft has taken a stunning debris that few out over a distance of about 15km. test image following its launch in DecemberNASA 2013.launched the Mars reconnaissance Orbiter the shot, shown right, a dense of 2005. it entered Mars’s orbit in March 2006. in August The new crater is not really blue; thisshows tint is a result of cluster enhanced to remove dust starscolourisation within the Largereddish Magellanic cloud, awww.nasa.gov/mro

Using the Very Large telescope in Chile, astronomers have found a nearby brown dwarf star with curiously red skies. Brown dwarfs are stars that are too small to ignite hydrogen fusion in their cores but too large to be considered planets. One brown dwarf that lies at least 100 lightyears away caught the attention of Federico Marocco from the University of Hertfordshire and his colleagues due to its that are too small to ignite unusually red atmosphere. hydrogen fusion in their “the thick clouds on this cores but too large to be considered planets. One particular brown dwarf brown dwarf that lies at are mostly made of mineral least 100 lightyears away dust,” says Marocco. the caught the attention of compounds include the Federico Marocco from magnesium-rich mineral the University of Hertfordshire and his enstatite and a crystalline colleagues due to its form of aluminium oxide.

NASA/JPL-CALteCh/UNiv. of ArizoNA, eSA/DPAC/AirbUS DS, NeiL J Cook, CeNter for AStroPhySiCS reSeArCh, UNiverSity of hertforDShire, NASA/JohNS hoPkiNS UNiverSity APPLieD PhySiCS LAborAtory/CArNegie iNStitUtioN of WAShiNgtoN

Mars gains a fresh crater

BroWn dWArf hAs red skies

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Io’s most enduring hotspots – it was glowing when it was frst detected by Voyager in 1979 and Rathbun Our experts examine the found that it was still going strong in 2007. New hottest new research Horizons was able to photograph several volcanoes repeatedly and found no variability in their brightness – they’re very stable in their intensity. 16 By far the brightest hotspot seen by New Horizons was a volcano called Tvashtar. It was such an intense thermal source that it didn’t just show up Images taken by the New Horizons probe are giving in images taken using an infrared flter, but also those us a greater insight into this highly volcanic moon taken in the red band. This was important because it allowed– itRathbun to work Io’s most enduring hotspots was glowing when out Tvashtar’s temperature. it was frst detected by Voyager in 1979 and Rathbun The hotter an object is, the shorter the Our experts examine the found that it was stillwavelength going strong in of 2007. lightNew it emits. The human body glows hottest new research Horizons was able to photograph several volcanoes in the far-infrared at about 10μm; a red-hot poker repeatedly and found no variability in their emits light at wavelengths a few microns long; light brightness – they’re very stable in their intensity. by the Sun peaks at about 0.5μm, shining By far the brightestemitted hotspot seen by New Horizons was a volcano called Tvashtar. It was such brilliantly at visible and ultraviolet wavelengths. By an intense thermal source that it didn’t just show up Images taken by the New Horizons probe are giving comparing the brightness of Tvashtar at both in images taken using an infrared flter, but also those us a greater insight into this highly volcanic moon infrared red wavelengths, Rathbun was able to taken in the red band. This was and important because it

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The violence of Io

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The violence of Io

allowed Rathbun to work out Tvashtar’s temperature. The hotter an object is, the shorter the wavelength of light it emits. The human body glows in the far-infrared at about 10μm; a red-hot poker emits light at wavelengths a few microns long; light emitted by the Sun peaks at about 0.5μm, shining brilliantly at visible and ultraviolet wavelengths. By comparing the brightness of Tvashtar at both infrared and red wavelengths, Rathbun was able to

“Pele was glowing when it was frst detected by Voyager “Pele was glowing in 1979 was still going when it and was frst detectedstrong by in 2007”

Voyagercalculate in 1979 the hotspot’s temperature to be about 950°C, which is the same as lava fows on Earth. and was still going Curiously, East Girru, the second-brightest thermal source seen on Io by New Horizons wasn’t strong in 2007”

I

o is the most volcanically active body in seen by Voyager in 1979, or Galileo in the late 1990s, the Solar System. It’s a fractious and violent calculate the hotspot’s to beany about ortemperature indeed from ground-based telescopes. East io seen through new Horizons instruments; to the study tvashtaras volcano littlethree world, and fascinating its near the moon’s 950°C, which is the same as lava fows on Earth. north pole is the brightest hotspot in each image, with a temperature of 950°C Girru lies 200km from a hotspot that was seen by face is constantly changing. We learned a Curiously, East Girru, the second-brightest Galileo, and so Rathbun has concluded that it’s a lot about Io from the Galileo probe’s tour of the thermal source seen on Io by New Horizons wasn’t o is the most volcanically active body in neworeruption. But,latewhen Jovian system between 1996 and 2001, and got seen by Voyager in 1979, Galileo in the 1990s,comparing the highestthe Solar System. It’s a fractious and violent or indeed from any ground-based telescopes. EastGalileo and New Horizons little world, and fascinating to studywhen as its the New resolution photos from a feeting glimpse most recently Girru lies 200km from hotspot that wasaround seen by East Girru, she couldn’t face is constantly changing. learnedon a its journey of athe landscape Horizons probe swung pastWeJupiter Galileo, and so Rathbun has concluded that it’s a lot about Io from the Galileo probe’s tour of the see any noticeable changes between the two, nor towards Pluto. new eruption. But, when comparing the highestJovian system between 1996 and 2001, and got anyGalileo lighter of the type that’s normally seen For a few days around 28 February 2007, New resolution photos from andregion New Horizons a feeting glimpse most recently when the New around volcanic sites on Io. So this new intense Horizons ablepast to Jupiter train its cameras of the landscape around East Girru, she couldn’t Horizons probewas swung on its journey on Io. It took see any noticeable changes between the two, nor towards Pluto. of Jupiter’s moon during this fyby and hotspot is something of a mystery: what’s the 200 photos any lighter region of the type that’s normally seen For a few days around 28 February 2007, New source of all that activity? Dr Julie Rathbun of the Planetary Science Institute around volcanic sites on Io. So this new intense Horizons was able to train its cameras on Io. It took in Tuscon and colleagues have written a paper hotspot is something of a mystery: what’s the 200 photos of Jupiter’s moon during this fyby and what they Many of the photos were source of all that activity? Drabout Julie Rathbun of theshow. Planetary Science Institute Lewis DartneLL is an Jupiter have was written eclipsing Io, casting a in taken Tusconwhen and colleagues a paper astrobiology research about what they Many of the photos–were shadow overshow. the moon’s surface perfect for Lewis DartneLL was reading… Io’s active volcanoes Lewis DartneLLfellow is an at the University of taken when Jupiter was eclipsing Io, casting a hunting for glowing volcanic areas. astrobiology research during the New Horizons era: Insights from New Horizons Leicester. His new book shadow over the moon’s surface – perfect for Lewis DartneLL was reading… Io’s active volcanoes fellow at the University of Most of the volcanoes observed by the Galileo imaging by J A rathbun et al. hunting for glowing volcanic areas. The Knowledge will be during the New Horizons era: Insights from New Horizons Leicester. His new book probe still active when Horizons few Most of were the volcanoes observed by New the Galileo published in April. imaging by J A rathbunread et al. it online at http://dx.doi.org/10.1016/ The Knowledge will be probe were active whenOne Newof Horizons few is among j.icarus.2013.12.002 past, sixstill years later. them, Pele, read it online at http://dx.doi.org/10.1016/ published in April.

NASA/JohNS hopkiNS UNiverSity Applied phySicS lAborAtory/SoUthweSt reSeArch iNStitUte

NASA/JohNS hopkiNS UNiverSity Applied phySicS lAborAtory/SoUthweSt reSeArch iNStitUte

io seen through three new Horizons instruments; the tvashtar volcano near the moon’s north pole is the brightest hotspot in each image, with a temperature of 950°C

I

past, six years later. One of them, Pele, is among



j.icarus.2013.12.002

Bulletin APRIL 17

news in

What makes stars explode?

brief

NASA’s NuSTAR may have uncovered why stars become violently unstable The mysTery of how stars explode might fnally main shock wave would stall, preventing the star be solved. X-ray observations taken by NAsA’s from shattering. NusTAr revealed that titanium Nuclear spectroscopic Telescope Array (NusTAr) is concentrated in clumps at Cassiopeia A’s centre. suggest material in soon-to-explode stars sloshes Astronomers conclude from this that material in Bulletin APRIL 17 around violently, energising a shock wave the former star sloshed around, re-energising that blows the star to smithereens. the shock wave that fnally made it NusTAr was launched into blast off its outer layers. low-earth orbit in June “stars are spherical 2012. Now it has created balls of gas, so you the frst NuSTAR map of may have uncovered why stars become violently unstable might think that NASA’s radioactive material when they end their JoiN THe HuNT The of how stars explode might fnally main shock wave would stall, preventing the star in mysTery a supernova lives explode, foRand plANeTARy be solved. X-ray observations taken by NAsA’s from shattering. NusTAr revealed that titanium remnant, that explosion SySTemS Nuclear spectroscopic Telescope Array (NusTAr) is concentrated in clumps at Cassiopeia A’s centre. NASA is asking help Cassiopeia A, would look for like suggest material in soon-to-explode stars sloshes Astronomers conclude from this that material in in fnding embryonic which lies energising a shock wave a uniform ball around violently, the former star sloshed around, re-energising planetary systems in that blows11,000 the star to smithereens. the shock wave that fnally made it about expanding observations from the NusTAr was launched into blast off its outer layers. Wide-feld Infrared lightyears out,” says low-earth orbit in June “stars are spherical Survey Explorer (WISE) from us. NusTAr 2012. Now it has created balls of gas, so you spacecraft. There may be Cassiopeia scientist fiona thousands lurking in the the frst map of A might think that data, but they can only be radioactive when they end their formed material when harrison from found through human in aa supernova lives and explode, massive star the California inspection, which poses a remnant, that explosion exploded after Institute of huge challenge. Cassiopeia A, would look like “Volunteers help the running Technology.will “our which lies out of a uniform ball astronomical community fuel; the light of this new results about 11,000 expanding discover newshow planetary lightyears out,” says detonation reached how nurseries the explosion’s that will become from us. roughly 300 years NusTAr engine future targets for NASA’s earth is distorted, Hubble Space Telescope Cassiopeia A scientist fiona ago. During the blast, high possibly because the inner and its successor, the formed when harrison from James Webb Space temperatures made lighter slosh around a massive star the regions Californialiterally Telescope,” says James elements before exploded afterfuse into heavier ones, Institute of detonating.” Garvin from NASA’s running out ofNusTAr has created a Heavy isotope titanium-44, imaged byTechnology. and now The “our NusTArGoddard map also casts Space Flight fuel; the light of this show NuSTAR and shown in blue, is clearlynew results Center in Maryland. map of one of the heavy isotopes doubt on another model of detonation reached how the explosion’s clustered at the centre of the explosion in Cassiopeia A, titanium-44. supernovae, inwww.diskdetective.org which a star earth roughly 300 years engine is distorted, The map resolves some puzzles about rotates rapidly enough to launch energetic jets ago. During the blast, high possibly because the inner temperatures made lighter the explosion, a shock wave literallythe slosh around Although there’s supernovae. During of gasregions that drive explosion. elements fuse into heavier before of detonating.” somehow blasts the ones, star apart, yet previous evidence jets in Cassiopeia A, NusTAr’s Heavy isotope titanium-44, imaged by and now NusTAr has created a The NusTAr map also casts computer simulations of thisNuSTAR process suggest they did not trigger the blast. andfailed shown to in blue, is clearlyobservations map of one of the heavy isotopes doubt on another model of clustered at the centre of the explosion replicate this. Instead they suggested that the www.nasa.gov/nustar in Cassiopeia A, titanium-44. supernovae, in which a star The map resolves some puzzles about supernovae. During the explosion, a shock wave somehow blasts the star apart, yet previous computer simulations of this process failed to replicate this. Instead they suggested that the

rotates rapidly enough to launch energetic jets of gas that drive the explosion. Although there’s evidence of jets in Cassiopeia A, NusTAr’s observations suggest they did not trigger the blast. www.nasa.gov/nustar

news in

brief

NASA is asking for help in fnding embryonic planetary systems in observations from the Wide-feld Infrared Survey Explorer (WISE) spacecraft. There may be thousands lurking in the data, but they can only be found through human inspection, which poses a huge challenge. “Volunteers will help the astronomical community discover new planetary nurseries that will become future targets for NASA’s Hubble Space Telescope and its successor, the James Webb Space Telescope,” says James Garvin from NASA’s Goddard Space Flight Center in Maryland. www.diskdetective.org

AT lAST: A GlobAl mAp of GANymede

More than four centuries after its discovery, the Solar System’s largest AT lAST: A GlobAl moon – Jupiter’s mAp of GANymede Ganymede – fnally has More than four centuries a global map. Wes after its discovery, the Patterson from the Johns Solar System’s largest Hopkins University in moon – Jupiter’s Maryland and colleagues Ganymede – fnally has compiled it using images a global map. Wes Patterson from the Johns from NASA’s Voyager Hopkins University in and Galileo missions.

HoW STARS CARVE STRANGE NEbUlAE

AStrONOmiCO NACiONAL/SPAiN) NASA/huBBLe/StSCi, uSGS

NASA/JPL-CALteCh/CXC/SAO, NASA/eSA & VALeNtiN BuJArrABAL (OBSerVAtOriO NASA/JPL-CALteCh/CXC/SAO, NASA/eSA &uSGS VALeNtiN BuJArrABAL AStrONOmiCO NACiONAL/SPAiN) NASA/huBBLe/StSCi,

(OBSerVAtOriO

What makes stars explode?

JoiN THe HuNT foR plANeTARy SySTemS

Low-mAss sTArs like the sun can end their lives as double-lobed planetary nebulae if they have close companions, a new study suggests. sun-like stars eventually out their Low-mAss sTArs like the sun canpuff end their atmospheres toplanetary form a ghostly cloud lives as double-lobed nebulae ifglowing they have a new study suggests. ofclose gas –companions, a ‘planetary nebula’ – while the core sun-like stars eventually their to be mostly shrinks. These were puff onceoutthought atmospheres to form a ghostly glowing cloud spherical, but some possess bipolar jets. of gas – a ‘planetary nebula’ – while the core This, theorises Blackman of the University shrinks. These were onceeric thought to be mostly of rochester in New york, could spherical, but some possess bipolar jets. be due to the This, theorises eric Blackmanofofathe University star or gravitational infuence companion of rochester in New york, could be due to the massive planet. The crucial factor is that the pair gravitational infuence of a companion star or mustplanet. be very together. massive Theclose crucial factor is that the pair www.rochester.edu must be very close together.

HoW STARS CARVE STRANGE NEbUlAE

www.rochester.edu

Maryland and colleagues compiled it using images from NASA’s Voyager and Galileo missions.

imaged by the Hubble Space Telescope, this pre-planetary nebula’s imaged by the Hubble Space Telescope, this bipolar jets are clear to see pre-planetary nebula’s bipolar jets are clear to see



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what’s on april 19

What’s on

yuri’s Night seething Observatory, Thwaite st mary, Norfolk, 12 April, 2pm onwards

Norwich Astronomical Society is just one of the astronomy groups in the UK hosting a Yuri’s Night party to celebrate the frst manned spacefight. what’s on april 19 With solar viewing, rocket making and more during the day, Oyuri’s F THNight E plus observing at night, this is an event for all the family. Mseething ONTH Observatory,Tickets Thwaitecost st mary, Norfolk, £3.50 for adults and £1.50 for children. You 12 April, 2pm onwards can fnd out more at www.norwichastro.org.uk.

Our pick of the best events from around the UK

AstroCamp 2014

What’s on Brecon Beacons, Wales, 26-29 April

Our pick of the best events from around the UK

AstroCamp 2014

PICK

OF THE MONTH

Brecon Beacons, Wales, 26-29 April

Whether you pitch or park, fnding room to

PICK

Norwich Astronomical Society is just one of the astronomy groups in the UK hosting a Ayton Village hall, scarborough Yuri’s Night party to celebrate the frst manned spacefight. With solar viewing, rocket making and more during the day, plus observing at night, this is an event for all the family. Tickets cost £3.50 for adults and £1.50 for children. You can fnd out more at www.norwichastro.org.uk.

Active galactic Nuclei 11 April, 7.30pm

Hear Dr Stuart Lumsden from Leeds University’s School of Physics and Astronomy discussing supermassive black holes at Active galactic Nuclei Scarborough Ayton Village hall, scarborough 11 April, 7.30pm and Ryedale Hear Dr Stuart Astronomical Lumsden from Society this month. Discover how these celestial leviathans Leeds University’s grow and the dramatic effect they have on the galaxies School of Physics and Astronomy around them. Tickets are free for members, £2 for non-members. discussing Visit www.scarborough-ryedale-as.org.uk.

supermassive black holes at Scarborough and Ryedale Astronomical pack your own equipment is advised Society this month. Discover how these museum celestial leviathans The herschel of Astronomy, Bath, grow and the dramatic effect they have on the galaxies 16 April to 18 December All activities plus a pitcharound for your tent them. Tickets are free for members, £2 for or caravan are included innon-members. the price ofVisit a www.scarborough-ryedale-as.org.uk. This new exhibition

Being Caroline herschel

astrocamp 2014/flickr, thinkstock, nasa/Jpl-caltech/cornell Univ./arizona state Univ

astrocamp 2014/flickr, thinkstock, nasa/Jpl-caltech/cornell Univ./arizona state Univ

Twice a year, the small village of Cwmdu in the Brecon Beacons is invaded by ticket (electricity can be supplied to your astronomers when AstroCamp rolls into pitch for an extra cost) but if you’re town. This month, the popular star party Caroline herschel planning on taking part in Being the evening returns to this beautiful site – a designated Whether you pitch or park, fnding room to pack your own equipment is advised The herschel observing festivities it’s worth bringingmuseum of Astronomy, Bath, Dark Sky Reserve. 16 April to 18 December All activities plusown a pitch for your tentand remember, TwiceAs a year, the small village of Cwmdu your equipment; well as observing at night, the or caravan are included in the price of a in the Brecon Beacons is invaded by This new exhibition at torches should be red light only. Tickets event will include talks, workshops and ticket (electricity can be supplied to your astronomers when AstroCamp rolls into the Herschel Museum of start at £38 per adult and £15 for children. a pub quiz with astronomical prizes pitch for an extra cost) but if you’re town. This month, the popular star party Astronomy celebrates the – including telescopes – to be won.planning on www.astrocamp.org.uk taking part in the evening returns to this beautiful site – a designated life and work of William Dark Sky Reserve. As well as observing at night, the event will include talks, workshops and a pub quiz with astronomical prizes – including telescopes – to be won.

at the Herschel Museum of Astronomy celebrates the life and work of William Herschel’s sister Caroline, an accomplished musician and astronomer in her own right. Admission is included in the general museum Herschel’s sister Caroline, entry fee, which is £6 for an accomplished musician adults and £3 for children. and astronomer in her own Find out more at www. right. Admission is included herschelmuseum.org.uk.

observing festivities it’s worth bringing your own equipment; and remember, torches should be red light only. Tickets start at £38 per adult and £15 for children. www.astrocamp.org.uk

behind the scenes

in the general museum entry fee, which is £6 for adults and £3 for children. Find out more at www. herschelmuseum.org.uk.

The sky AT NighT iN APriL Four, 13 April, 10pm (repeated

Four, 17 April, 7.30pm)*

more listings online

behind the scenes The sky AT NighT iN APriL Four, 13 April, 10pm (repeated

mArs visit our website at www. This month The Sky at Night will skyatnightmagazine.com/ Four, 17 April, journey 7.30pm)* across the face of our planetary more listings whats-on online for the full list of mArs neighbour – Mars. For more than 10 this month’s events from visit our website at www. This month years The Skywe’ve at Night hadwill a continuous presence around the country. skyatnightmagazine.com/ journey across the face of our planetary whats-on for the full list of on Mars, thanks to the Opportunity, neighbour – Mars. For more than 10 this month’s events from Spirit and Curiosity Together to ensure that your talks, years we’ve had a continuous presencerovers. around the country. observing evenings and star theytohave changed our understanding on Mars, thanks the Opportunity, Spirit and Curiosity rovers. Together to ensure of the Red Planet and redefned ourthat your talks,parties are included, please observing evenings and submit star your event by flling they have changed searchour forunderstanding extraterrestrial life. parties are included, please

of the Red Planet and redefned our in the submission form at the ground-level images taken by the martian *Check www.radiotimes.com as submit your event by flling times search for extraterrestrial life. bottom of the page. in the submission form at the rovers have given usbynew insights may vary ground-level images taken the martian rovers have given us new insights

*Check www.radiotimes.com as times may vary

bottom of the page.



A pAssion for spAce april 21

a passion for A pAssion for spAce april 21

a passion for with Maggie Aderin-Pocock

Listen carefully: sound could help us solve one of the enduring mysteries of the Universe

T

he famous of modern physics: tagline used to gravitational waves. advertise the The demise of a star 1979 flm can leave behind some Alien was “In space no interesting debris. Some one can hear you leave a white dwarf, scream”. Technically, some collapse to form that’s true. In the black holes while others he famous of modern physics: vacuum of space sound turn supernova and can tagline used to gravitational waves. waves are unable leave behind a neutron advertise the to The demise of a star 1979 as flm can leave behind some propagate there’s no star – a body the size of Alien was “In space no interesting debris. Some medium to carry them. a city (~10km) with the one can hear you leave a white dwarf, So why are the sounds of mass a little less than scream”. Technically, some collapse to form thetrue. Universe that’s In the the subject black holes while others 1.5 times that of our Sun. of March’s episode of A pulsar is a type of vacuum of space sound turn supernova and can waves unable to leave behind a neutron neutron star that emits a Theare Sky at Night? Well, The audible ‘footprint’ of propagate as there’s no has star – a body the size of beam of radiation that it’s because sound a gravitational wave medium to carry them. a city (~10km) with the helped us discover some appears to pulsate – a bit could be detected in a So why are the sounds of mass a little less than pulsar’s radiation beam amazing things about the Universe the subject 1.5 times that of our Sun. like the light from a bodies lighthouse – due to a of celestial March’s episode of and may A pulsar is a type of The Sky at Night? Well, neutron star that emits a help us solve one of theThemysteries that of misalignment between its rotational and surface of the Sun. The oscillations were audible ‘footprint’ it’scontinues because sound has of radiationaxes. that If this beam is in the right to puzzle us.a gravitational wave detected by measurements of red or blue beammagnetic helped us discover some appears to pulsate – a bit could be detected in a orientation, its radio waves can be detected shifts of small surface patches, which were like the pulsar’s radiation beam amazing things about light from a on Earth and able to tell us if the area being observed celestial bodies and may lighthouse – due to a heard as a clicking sound. help usfrst solveencounter one of the mysteries that in space its rotational andof the clicking can be surface of thewas Sun.moving The oscillations were frequency towards or awaymisalignment from us. betweenThe My with sounds continues to puzzle magnetic is in thestable. right So stable, in fact, that it detected by measurements of of redthe or blue incredibly The source oscillations was axes. If this beam came with the us. Cassini-Huygens space its radio waves can be detected surface patches, which were may enable us to detect a gravitational unknown at the time and it orientation, was suggested probe. After its seven-year journey ofshifts of small on Earth and heard as a clicking sound. able to tell us if the area being observed Good vibrations wave, can as abewave’s presence could cause a that they were due to sound waves more than 1.5 billion km the spacecraft The frequency of the clicking was moving towards or away from us. My frst encounter with sounds in space minuscule delay insidewas the Sun. Observations arrived at Cassini-Huygens Saturn and released incredibly stable. So stable, in fact, that it in the arrival the pulse’s The sourcegenerated of the oscillations came with the space the Huygens enableofus to detectclicks a gravitational unknown at later the time and it was this suggested probe. Afterwhich its seven-year journey of on Earth. If a delay is found in a confrmed and themay science lander, tumbled through the dense wave, could cause a due to sound waves more than 1.5 billion km the spacecraft number of pulsars then the passing of a helioseismology was born. Just asas a wave’s presence atmosphere of Saturn’s moon Titan.that It they were minuscule delay in the arrival the pulse’s arrived at Saturn and released the Huygens generated inside the Sun. Observations gravitational wave could be detected. seismologists here on Earth can use sent back sounds and images as it fell, and clicks on Earth. If a delay is found in a later confrmed this and the science of lander, which tumbled through the dense Sopassing even ifofscreaming is futile, listening is tectonic events planet’s I remember beingmoon amazed of pulsars then the a was born. Just to as probe ournumber atmosphere of Saturn’s Titan.atIthearinghelioseismology not, as the detection of sound waves and interior, so similar techniques can be used sounds from bodies in our Solar System. gravitational wave could be detected. seismologists here on Earth can use sent back sounds and images as it fell, and So even if screaming is futile, listening is tectonic events to probe our planet’s I remember being amazed at hearing oscillations out there is giving us new to probe the Sun and reveal structure that Now we’re doing more with sound and not, as the detection of sound waves and interior, so similar techniques can be used sounds from bodies in our Solar System. insight into the Universe around us. we otherwise could not see. we don’t have to send up a spacecraft to oscillations out there is giving us new to probe the Sun and reveal structure that Now we’re doing more with sound and Now it’s hoped that oscillations detect it, as vibrations emanating from a insight into the Universe around us. we otherwise could not see. we don’t have to send up a spacecraft to Maggie Aderin-Pocock is a space scientist generated by other objects in space could body can sometimes be seen. Now it’s hoped that oscillations detect it, as vibrations emanating fromIn a the early co-presenter Aderin-Pocockand is a space scientist of The Sky at Night S generated other objects in spaceone could body can sometimes be seen. the early over used to detect of the Maggie true enigmas 1960s oscillations wereInobserved the bybe

with Maggie Aderin-Pocock

Listen carefully: sound could help us solve one of the enduring mysteries of the Universe

T

thinkstock

thinkstock

Good vibrations

1960s oscillations were observed over the

be used to detect one of the true enigmas

and co-presenter of The Sky at Night

S



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exoplanet excursions april 23

jon culshaw’s

ex planet excursions exoplanet excursions april 23

jon fnds himself on a world so steeped in darkness that the stars cast shadows

jon culshaw’s

a technique called gravitational Sitting at the controls of the they cast shadows. it’s novel to notice that microlensing is used to detect rogue Cruiser globe, i’m gripped by an urge the stars in this rogue planet’s sky never planets back on earth, but there’s no need move. Very soon it’s disconcerting, even to experience the unfathomable infnity for such methods today as this particular of the Universe. Such an overused word, frustrating that the entire night sky here is rogue planet is right in front of me. i land an unvarying, motionless mural. Due to ‘awesome’: reasonably priced Florida immediately to experience the feeling of doughnuts may be described in a twangy not being in a conventional orbit and this lonesome world. Miley Cyrus tone as ‘awesome’, but the because any rotation of this planet on its the view from the surface is a palette vastness of the Universe is awesomeness axis has become so imperceptibly slow, the of charcoal grey andthat opaque in the truehimself sense. i hit and head stars in this alien sky wouldn’t appear to jon fnds onlaunch a world so steeped in darkness theblackness, stars cast shadows like my grandmother’s monochrome off in a random direction. change in an entire human lifetime. Sir a technique called gravitational Sitting at the controls of the they cast shadows. it’s novel to notice that Pye tV with the brightness at minimum. Soon the Cruiser globe’s scanning would’ve microlensing is used to detect rogue Cruiser globe, i’m gripped by an urge the stars in this roguePatrick planet’s sky never had this dark sky entirely is a rocky world interspersed with an unknown observed, sketched and catalogued in planets backthis on earth, but there’s no need to systems experienceindicate the unfathomable infnityobject. move. Very soon it’s disconcerting, even for such methods todayresembling as this particular of ithe Universe. Suchsimilar an overused word, frustrating night hereleaving is features massive lakes ofthat ice.the entire feel a concern to Captain under a sky week, him plenty of time rogue planet is right in front of me. i land ‘awesome’: reasonably priced Florida an unvarying, motionless mural. Due to if there’s radioactive decay happening Phillips when he spotted the Somali for cricket and a g&t in the pavilion. immediately to experience the feeling of doughnuts may be described in a twangy being in a conventional orbit and in the planet’s core, it mightnot generate pirates looming. But drawing closer, this desolate place conveys a strange this lonesome world. Miley Cyrus tone as ‘awesome’, but the because any rotation of this planet on its enough heat for lakes toaxis be has liquifed the great revealed: this object feeling of slow, sadness. the view from the surface is athe palette vastness of themystery Universe is is awesomeness become so imperceptibly the it seems impossible deeper down. rogue planet. a solitary world of charcoal grey and opaque blackness, not to project human emotions onto this in is theatrue sense. i hit launch and head stars in this alien sky wouldn’t appear to like my grandmother’s monochrome offdrifting in a random direction. change lifetime. SirFeeling pity for a planet: there are those who believe it’sin an entire human through the Universe, devoid environment. Pye tV withpossible the brightness at minimum. wandering Soon the Cruiser globe’s scanning Patrick would’ve had this dark sky entirely for earth-sized of a parent star. what a bizarre sensation. i decide to this is a rocky world interspersed with systems indicate an unknown object. observed, sketched and catalogued in planets like this one to retain an there’s a tantalising blend of name this lonely world ‘Obsidiana’. features resembling massive lakes of ice. i feel a concern similar to Captain under a week, leaving him plenty of time atmosphere, perhaps of thick fascination foreboding in pavilion. my imagination i hear the piano if there’s radioactive decay happening Phillips when heand spotted the Somali on for hydrogen. cricket and a g&t in the Combine thisgenerate with enough subterranean core, it might pirates looming. But drawing this desolate place conveys a strange approaching this worldcloser, that was in the planet’s theme from the Bill Bixby-era Incredible enough heat for the lakes to be liquifed thesomehow great mystery is revealed: this object feeling of sadness. it seems impossible geological activity and there could be ejected from its system, Hulk tV show as the rogue planet deeper down. is a rogue planet. a solitary world not to project human emotions onto this suffcient warmth generated to support perhaps by a gravitational encounter Obsidiana drifts silently through the there are those who believe it’s drifting through the Universe, devoid environment. Feeling pity for a planet: thesewandering disconnected planets notsensation. another Universe possible for life. earth-sized of with a parent star. object. it’s estimated there what a are bizarre i decidein to her own sweet way. without the most intriguing potential. are around two rogue planets for every planets like this one to retain an there’s a tantalising blend of name this lonely world ‘Obsidiana’. of thick hydrogen. fascination andgalaxy. foreboding on scientists atmosphere, perhaps in blackness my imagination iJon hearCulshaw the piano is a comedian, impressionist this alien sky of the deepest star in the Some Combine this with enough subterranean piercing approaching thismay worldbe that was more. theme from the Bill Bixby-era Incredible guest on The Sky at Night and occasional has stars so magnifcently that think there many

ex planet

main illustration by mark garlick, photo: Emma samms

main illustration by mark garlick, photo: Emma samms

excursions

somehow ejected from its system, perhaps by a gravitational encounter with another object. it’s estimated there are around two rogue planets for every star in the galaxy. Some scientists think there may be many more.

geological activity and there could be suffcient warmth generated to support life. these disconnected planets are not without the most intriguing potential. this alien sky of the deepest blackness has stars so magnifcently piercing that

Hulk tV show as the rogue planet Obsidiana drifts silently through the Universe in her own sweet way.

Jon Culshaw is a comedian, impressionist and occasional guest on The Sky at Night

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26

Interactive Emails • lEttErs • twEEts • FaCEBOOK

this month’s Email us at [email protected] 26 top prize: four Philip’s books

Interactive message of the month

The ‘Message of the Month’ writer will receive four top titles courtesy of astronomy publisher Philip’s. Heather The more I see her on TV, the more my admiration Couper and Nigel for Dr Maggie Aderin-Pocock grows. Her obvious Henbest’s Stargazing 2014 is a month-by-month guide is contagious and engaging – she lights Emailenthusiasm us at [email protected] to the year and you’ll be up the screen every time she appears. Something able to fnd all the best she seems to share with the late, great Sir Patrick is sights with Patrick Moore’s her ability to speak plain English, even when going The Night Sky. Stargazing The ‘Message of the Month’ into technical detail. withwillBinoculars writer receive fourby topRobin When I heard she was to become a Sky at Night Scagell and David Frydman titles courtesy of astronomy presenter in February, I was thrilled. I believe she publisher Philip’s. Heather and contains equipment The more I see her on TV, ambassador the more my admiration Couper and Nigel will be a great for astronomy and a observing guides, and for Dr Maggie Aderin-Pocock grows. Her obvious Henbest’s Stargazing 2014 superb role model for the young. I’m looking you’ll be viewing planets, is a month-by-month guide enthusiasm is contagious and engaging – she lights galaxies and more forward theshe next episode of The Sky at Night to the year and you’ll be up the screen everyto time appears. Something able to fnd all the best with Storm Dunlop’s and wishwith Maggie allgreat the Sir best. she seems to share the late, Patrick is sights with Patrick Moore’s Practical Astronomy. her ability to speakthanks plain English, even when going Binocular Also, for Stephen Tonkin’s The Night Sky. Stargazing into technical detail. tour, it’s been a godsend on these stormy nights with Binoculars by Robin When I heard she was to become a Sky at Night Scagell and David Frydman whenever there’s been a brief break in the clouds. presenter in February, I was thrilled. I believe she contains equipment and seem for to have beenand really will be a The greatskies ambassador astronomy a clear despite observing guides, and superb role for the young. I’m looking all model the foul weather! you’ll be viewing planets, galaxies and more forward George to the next episode of The Sky at Night Futers, Peebles with Storm Dunlop’s and wish Maggie all the best. Practical Astronomy. Also, thanks for Stephen Tonkin’s Binocular We agree George, don’t forget to read Maggie’s tour, it’s been a godsend on these stormy nights excellent column on page 21. – Ed whenever there’s been a brief break in the clouds. The skies seem to have been really clear despite all the foul weather!

Mad about Maggie

Emails • lEttErs • twEEts • FaCEBOOK

this month’s top prize: four Philip’s books

message of the month

bbc

Mad about Maggie

Þ Dr Maggie Aderin-Pocock is skilled at communicating her knowledge of and enthusiasm for astronomy

Catch them young

bbc

George Futers, Peebles

new uses for old scopes

We agree George, don’t forget to read Maggie’s Þ Dr Maggie Aderin-Pocock is skilled at communicating Sunday morning free of andHow saddened I was to learn via Govert Schilling’s her knowledge enthusiasm for astronomy excellentOn column on page 21. – Ed recently I had an hour

before lunch to read BBC Sky at Night Magazine. But article (‘Observing in an uncertain future’, March) within 10 minutes that idea was shattered, as my just how many perfectly serviceable – and sizeable daughter arrived for a visit, bringing my seven-uses for – telescopes in Chile are being mothballed or Catch them young new old scopes month-old granddaughter Emily with her. Emily decommissioned. What a waste. On Sunday morning recently I had an hour free How saddened I was to learn via Govert Schilling’s þ Seven-month-old Emily to read BBCcomfortable Sky at Night Magazine. But and article (‘Observing in an uncertain future’, made herself on my knee I imagine I’m notMarch) the only reader to have made a gets to grips with BBC before Sky lunch within 10proceeded minutes thattoidea was shattered, as my how many perfectly serviceablebetween – and sizeable at Night Magazine cast her eyes over the pagejust I was connection that and Kieron Allen’s piece daughter arrived for a visit, bringing my seven– telescopes in Chile are being mothballed or reading. After a while, she about robotic scopes (‘Imaging from afar’) later in month-old granddaughter Emily with her. Emily decommissioned. What a waste. þ Seven-month-old Emily lost interest and opted for theonly same issue. Couldn’t made herself comfortable on my knee and I imagine I’m not the reader to have made a some of the Chilean gets to grips with BBC Sky theI more taskbetween of observatories be added at Night Magazine proceeded to cast her eyes over the page was interesting connection that and Kieron Allen’s pieceto those that are already reading. Afterriding a while,the she hobbyhorse. about robotic scopesremotely (‘Imaging from afar’) later in I did accessible to fee-paying users? Although lost interest and opted for the same issue. Couldn’t some of the Chilean my best to guide her towards perhaps there’s another potential use these the more interesting task of observatories be added to those that are already the astronomy path, but telescopes could be put to? riding the hobbyhorse. I did remotely accessible to fee-paying users? Although maybe it was a bit too early! is use a growing realisation and acceptance my best to guide her towards perhaps there’s anotherThere potential these that near-Earth objects (NEOs) are far more Geoff Wadsley, the astronomy path, but telescopes could be put to? maybe it was aWellingborough bit too early! There is a growingnumerous realisation and acceptance than previously thought, and that that near-Earth objects (NEOs) are far more Geoff Wadsley, even relatively small ones are capable of doing numerous than previously thought, and that Wellingborough damage to our planet. Britain has its own Maybe seven months is a bit even relatively small extreme ones are capable of doing Spaceguard Centre the English-Welsh border ambitious but don’t extreme damage to our planet. Britain has itson own Maybe seven months is a bitGeoff, thethere English-Welsh border ambitious Geoff, and are others scattered around the world givebutupdon’t yet! – EdSpaceguard Centre on give up yet! – Ed



and there are others scattered around the world

letters APRIL 27

that report newly identifed NEOs to a centre in Boston, US.My understanding is that there is a shortage of telescopes that are large enough to be able to see these smaller objects dedicated to this important area of observation. I wonder if the Chilean ones might be pressed into service? David Tart, Walsall

the big

Great idea David, it would be real shame to let these historic observatories close down altogether. – Ed

debate

BBC Sky at Night Magazine is published by Immediate Media Company Bristol Limited under licence from BBC Worldwide, who help fund new BBC programmes. EDITORIAL Editor Chris Bramley Art Editor Steve Marsh Production Editor Kev Lochun Onlineletters Editor KieronAPRIL Allen 27 Staff Writer Elizabeth Pearson Reviews Editor Paul Money

a successful comeback

that report newly identifed NEOs to a centre in CONTRIBUTORS Paul Abel, Sean Blair, Paul F Cockburn, Adam Crute, Maggie Boston, US.My understanding is that there is a in the that lateare 1950s early Aderin-Pocock, Jon Culshaw, Lewis Dartnell, Glenn Dawes, shortageBack of telescopes largeand enough to 1960s, I was bitten Mark Garlick, Will Gater, Alastair Gunn, Nicky Guttridge, space andobjects astronomy bug. But, asBBCwith many be able toby seethe these smaller dedicated Sky at Night Magazine is published by Immediate Media Carollicence Lakomiak, Pete Lawrence, Martin Lewis, Chris Lintott, Company Bristol Limited under from BBC Worldwide, to this important area of observation. I wonder young people, this all came to an end when I Hazel Muir, Steve Richards, Steve Sayers, Paul Sutherland, who help fund new BBC programmes. ones school might beand pressed fnished went out into the big wide @skyatnightmag if the Chilean Stephen Tonkin, Emily Winterburn EDITORIAL into service?

Have your say at http://twitter.com/ skyatnightmag

asked: How have

world. Now, newly retired, I’ve returned to Chris the fold. Editor Bramley ADVERTISING SALES Art Editor Steve Marsh I quickly realised that science and technology Advertising Director Caroline Herbert Production Editor Kev Lochun Onlinesince Editor Kieron AllenAdvertising Managers Steve Grigg (0117 314 8365), have moved onbea real great dealtoin I rare breaks in the clouds Great idea David, it would shame letthe these50 years Staff Writer Elizabeth Pearson Tony Robinson (0117 314 8811) – Ed looking last gazed close up atdown the altogether. sky, so I began around this stormy season? historic observatories Reviews Editor Paul Money Inserts Laurence Robertson (00 353 87 690 2208) debate for a suitable magazine that would helpCONTRIBUTORS me learn a successful comeback Have your say at Paul Abel,BBC Sean Blair, Paul FPRODUCTION Cockburn, Adam Crute, Maggie about astronomy today. when I found @Ripley180924609 Back in the late 1950s and early 1960s,That’s I was bitten http://twitter.com/ Production Director Aderin-Pocock, Jon Culshaw, Lewis Dartnell, GlennSarah Dawes,Powell Skyand at Night Magazine. By being able to watchby the space Mark Garlick, Will Gater, Alastair Gunn,Manager Nicky Guttridge, skyatnightmag Production Derrick Andrews astronomy bug. But,Its as balance with manyof recurring Carol Lakomiak, Pete Lawrence, Martin Lewis, Chris Lintott, Ad Services Manager Paul Thornton young people, this all came anGuide end when sections such as to the to Ithe Universe and the as the #ISS passed over Hazel Muir, Steve Richards, Steve Sayers, Paul Sutherland, Ad Co-ordinator Emily Thorne fnished school and went out into the big wide @skyatnightmag Stephen Big Questions, combined with observing tips,Tonkin, Emily Winterburn – frst time I’ve ever seen Ad Designers Cee Pike, Andrew Hobson world. Now, newly retired, I’ve returned to the fold. asked: How have ADVERTISING SALES monthly charts and excellent articles have all helped it and it was fab. :-) Reprographics Tony Hunt, Chris Sutch I quickly realised that science and technology you made the most of the Advertising Director Caroline Herbert enormously to rekindle my interest. Advertising Managers Steve Grigg (0117 314 8365), have moved on a great deal in the 50 years since I rare breaks in the clouds LICENSING Tony Robinson (0117 314 8811) With background in communications, I’ve last gazed up at thea sky, so I began looking around this@sjb_astro stormy season? Head of Licensing and Syndication Joanna Marshall Inserts Laurence Robertson (00 353 87 690 2208) magazine that would helpworld me learn decided to delve into the of radio astronomy. Left scope all set up in for a suitable MARKETING PRODUCTION about astronomy today.anything That’s when I found BBC I don’t @Ripley180924609 Apart from else, it means have to Sarah Powell garage ready to quickly Production Director Head of Circulation Rob Brock Sky at Night Magazine. Its balance of recurring By being able to watch Production Manager Derrick Andrews Head of Marketing Jacky Perales-Morris go out into the cold! In the few months that I’ve take out during rare Ad Services Manager Paul Thornton sections such as the Guide to the Universe and the as the #ISS passed over Marketing Executive Chris Day Ad Co-ordinator Emily Thorne been combined reading your excellenttips, magazine, there hasn’t clear Observed Big Questions, with observing – frst timespells. I’ve ever seen HeadHobson of Press and PR Carolyn Wray (0117 314 8812) Ad Designers Cee Pike, Andrew chartsanything and excellent have allDo helped onarticles the subject. you have any Tony Hunt, Chris Sutch it and was fab.Jupiter :-) SNit2014J, and monthlybeen Reprographics PUBLISHING enormously to rekindle my interest. plans to cover the topic? the Moon. LICENSING Publisher Jemima Ransome David Tart, Walsall

you made the bigthe most of the

With a background in communications, I’ve @sjb_astro Head of Licensing and Syndication Joanna Marshall Brian Faulkner, Cornwall Managing Director Andy Marshall decided to delve into the world of radio astronomy. Left scope all set up in MARKETING @thephildoyle Apart from anything else, it means I don’t have to garage ready to quickly MANAGEMENT Head of Circulation Rob Brock Marketing Jacky Perales-Morris I’mtheglad we’ve able tothat helpI’verekindleHead youofpassion I read a billion Chairman Stephen Alexander cold! In thebeen few months take out during rare reviewsgo out into Marketing Executive Chris Day Deputy Chairman Peter Phippen been reading your excellent magazine, clear spells. Observed for astronomy Brian. Keepthere yourhasn’t eyes peeled for our and blogs to shortlist the Head of Press and PR Carolyn Wray (0117 314 8812) CEO Tom Bureau thearticle subject.on Doradio you have any observations SNbest 2014J, Jupiter and How on to… meteor planetary camera,been anything PUBLISHING plans to cover the topic? the Moon. coming up in next month’s issue. – Ed Publisher Jemima RansomeBBC WORLDWIDE, UK PUBLISHING new or used, for circa Brian Faulkner, Cornwall Managing Director Andy Marshall Director of UK Publishing Nicholas Brett £200. @thephildoyle Head of UK Publishing Chris Kerwin MANAGEMENT Head of Editorial, UK Publishing Jenny Potter I’m glad we’ve been able to help rekindle you passion I read a billion reviews Chairman Stephen Alexander Deputy Chairman Peter Phippen UK Publishing Coordinator Eva Abramik for astronomy Brian. Keep your eyes peeled for our and blogs to shortlist the This is a picture I took with @EardleyTony CEO Tom Bureau [email protected] How to… article on radio meteor observations best planetary camera, just my refractor scope and Imaged a new oncewww.bbcworldwide.com/uk--anz/ukpublishing.aspx BBC WORLDWIDE, UK PUBLISHING coming up in next month’s issue. – Ed new or used, for circa

Caught on camera

of UK Publishing Nicholas Brett my camera phone. IDirector didn’t EDITORIAL ADVISORY BOARD Deborah Cohen, Andrew Cohen, Head of UK Publishing Chris Kerwin use any Moon flters. Michael Caught on camera Head of Editorial, UK Publishing JennyEwing, Potter Julian Hector, John Lynch, Jonathan Renouf

in-a-lifetime supernova in M82.

£200.

@EardleyTony Imaged a new once@haddockman83 in-a-lifetime supernova Had a good look at in M82.

the Moon through binoculars and managed to see the @haddockman83 Had a good look at the rings of Jupiter through Moon through binoculars a telescope. and managed to see the rings of Jupiter through @smyth791 a telescope.

UK(aged Publishing Coordinator Eva Abramik This is a picture I took with Alisia Maldon-Stanley 15), [email protected] SUBSCRIPTION RATES just my refractor scope and London www.bbcworldwide.com/uk--anz/ukpublishing.aspx Annual subscription rates (inc P&P): UK cheque/credit card £59.88; Europe & Eire my camera phone. I didn’t Airmail £69; rest of world airmail £79. To order, call 0844 844 0260 EDITORIAL ADVISORY BOARD Deborah Cohen, Andrew Cohen, use any Moon flters. Michael Ewing, Julian Hector, John Lynch, Jonathan Renouf

What a(aged fantastic Alisia Maldon-Stanley 15), shot Alisia, keep © Immediate Media Company Bristol Limited 2014 SUBSCRIPTION RATES ISSN 1745-9869 going with the astrophotography, London Annual subscription rates (inc P&P): UK cheque/credit card £59.88; Europe & Eire

All rights reserved. No part of BBC Sky at Night Magazine may be reproduced in any form or by means

£69; rest of–world order,orcall 0844without 844 0260 eitherTowholly in part, prior written permission of the publisher. Not to be re-sold, lent or hired you’ve obviously gotAirmail a talent. Edairmail £79. out or otherwise disposed of by way of trade at more than the recommended retail price (subject to VAT

What a fantastic shot Alisia, keep

© Immediate Media Company Bristol Limited 2014 ......................................................................................... ISSN 1745-9869 going with the astrophotography,

in the Republic of Ireland) or in mutilated condition.

Immediate Media Company Bristol Limited is working to ensure that all of its paper is sourced from

rights reserved. No part of BBC Sky at Night Magazine may be reproduced in any form or by means OOPS! you’ve obviously got a talent. – Ed All well-managed forests. ThisNot magazine is printed on Forest Stewardship Council (FSC) certifed paper. This either wholly or in part, without prior written permission of the publisher. to be re-sold, lent or hired out or otherwise disposed of by way of trade at more than (subject to VAT magazine can the be recommended recycled, forretail use price in newspapers and packaging. Please remove any gifts, samples or in the Republic of Ireland) or in mutilated condition. • In March 2014’s First Light review of the Celestron wrapping and dispose of it at your local collection point. ......................................................................................... Immediate Media Company Bristol Limited is working to ensure that all of its paper is sourced from score As soon as the clouds OOPS! Skyris 445C colour imaging camera, the overall well-managed forests. This magazine is printed on Forest Stewardship Council (FSC) certifed paper. This magazine can be recycled, for use in newspapers and packaging. Please remove any gifts, samples or @smyth791 should been fourofstars, not three. 2014’shave First Light review the Celestron break, I have been out• In March wrapping and dispose of it at your local collection point.

As soon as the clouds looking at Jupiter and break, I have been out its amazing moons. :) looking at Jupiter and its amazing moons. :)

Skyris 445C colour imaging camera, the overall score READER SURVEY WINNER should have been four stars, not three.

Congratulations to the winner of our reader survey prize

READER SURVEY WINNER The publisher, editor and authors accept no responsibility in respect of any products, goods or services draw in thewinner December 2013 survey issue.prize Andy Offord from Congratulations to the of our reader that may be advertised or referred to in this issue for any errors, omissions, mis-statements or mistakes The publisher, editor and authors acceptinnoany responsibility in respect of any goods or services such advertisements orproducts, references. Stowmarket, Suffolk, 16GB iPad Mini. draw in the December 2013 issue. wins Andy a Offord from that may be advertised or referred to in this issue for any errors, omissions, mis-statements or mistakes in any such advertisements or references. Stowmarket, Suffolk, wins a 16GB iPad Mini.



28

Hotshots

This month’s pick of your very best astrophotos

28

Hotshots

PHOTO OF THE

MONTH

This month’s pick of your very best astrophotos

PHOTO OF THE

MONTH

 The Orion Nebula ANNA MORRIS, SuFFOLk, 5 DECEMbER 2013

Anna Thesays: Orion Nebula “I like this image as it shows just

BBC Sky at Night Magazine says: “The About Anna: “I started astro amount of detail Anna has been able to imaging back in 2008. I was the dynamic range of this nebula and the large capture in this pristine image of the Orion living in a light-polluted area Anna says: “I like this image as it shows just BBC Sky at Night Magazine says: “The About Anna: “I started astro array of colours in the region that you don’t see Nebula and its surroundings is amazing. We how much dust is around the Orion Complex, amount of detail Anna has been able to imaging back in 2008. I was and could not see much when viewing through It alsoin thisvery rarely wide-feld images of this corner thewell dynamic range of this nebula andan theeyepiece. large capture pristine imagesee of the Orion living in a light-polluted areathrough the new scope I had array of colours the region that youeven don’twith see modest Nebula and itsofsurroundings amazing. We shows whatincan be imaged space thatismanage, so expertly, to defne and could not see much got for Christmas due to all well when viewing through an patience eyepiece. Itand also time.” very rarely see wide-feld images this corner equipment given some the intricate dust of lanes on the periphery of thethrough the new scope I had the city lights. Short exposure shows what can be imaged even with modest of space that manage, so expertly, to defne got for Christmas due to all central nebulous region. From vibrant pinks the cityimages allowed me to make out more than I could equipment given some patience and time.” the intricate dust lanes on the periphery of the lights. Short exposure Equipment: Nikon D7000 DSLR camera,central Orionnebulous andregion. bluesFrom to the pastel, almost muddy, hues of through eyepiece. I got the bug from those vibrant pinks images allowed me to make out morethe than I could EON 80ED telescope. thepastel, dust almost lanes,muddy, this is hues the work of an expert.” frst Equipment: Nikon D7000 DSLR camera, Orion and blues to the of through the eyepiece. I got thephotographs bug from thoseand have been imaging since.” ANNA SuFFOLk, 5 DECEMbER 2013 Complex, howMORRIS, much dust is around the Orion

EON 80ED telescope.



the dust lanes, this is the work of an expert.”

frst photographs and have been imaging since.”

HOTSHOTS APRIL 29

HOTSHOTS APRIL 29

 The leaping puma in the Rosette Nebula kFIR SIMON, GAN-YAvNE, ISRAEL 18,30 AND 31 JANuARY 2014 kfr says: “I like this image because of all the dark nebulae in the lower part of the frame, which Theresemble leapingapuma parade of animals.“

inEquipment: the Rosette Nebula SbIG ST8300M CCD camera, Altair Astro 8-inch Ritchey-Chrétien astrograph, ASA

kFIR SIMON, GAN-YAvNE, ISRAEL DDM 6031PRO direct2014 drive mount. 18,30 AND JANuARY

kfr says: “I like this image because of all the dark nebulae in the lower part of the frame, which resemble a parade of animals.“ Equipment: SbIG ST8300M CCD camera, Altair Astro 8-inch Ritchey-Chrétien astrograph, ASA DDM 60 PRO direct drive mount.

 Jupiter and Europa TOM HOWARD, SuSSEx, 9 DECEMbER 2013

Tom Jupiter says: “Iand haveEuropa never been interested in theHOWARD, expenseSuSSEx, and extra effort required TOM 9 DECEMbER 2013

in using colour flters for imaging. This image showed Tom says: “I have never been interested in whatand canextra be achieved with one-shot theme expense effort required in a using colour flters for imaging. This image showed colour planetary camera under excellent  NGC 891 TONY FuNNELL, SuSSEx, NOvEMbER 2013 meseeing what can be achieved with a one-shot conditions.” colour planetary camera under excellent Tony says:NOvEMbER “This is a 2013 very popular galaxy that appears as a really dim line visually but develops SuSSEx, Equipment: Celestron Skyris 618C CCD TONY FuNNELL, seeing conditions.” great detail when it is withasaaCCD Tony says: “This is a very popular galaxyimaged that appears reallycamera.” dim line visually but develops camera, Celestron C11 Schmidt-Cassegrain,

 NGC 891

Equipment: Celestron Skyris 618C CCD Sky-Watcher EQ6Schmidt-Cassegrain, mount. camera, Celestron C11 Sky-Watcher EQ6 mount.

great detail when it is imaged with314 a CCD camera.” Equipment: Atik CCD camera,

8-inch Ritchey-Chrétien telescope, Sky-Watcher EQ6 mount.

Equipment: Atik 314 CCD camera, 8-inch Ritchey-Chrétien telescope, Sky-Watcher EQ6 mount.



30

30

 The Milly Way and Venus LuIS ARGERICH, ARGENTINA, 3 NOvEMbER 2013 Luis says: “Here’s a shot of the Milky Way at dusk with venus and the Moon just in the middle of it. Plenty of frefies decorate the scene. I like how the Milky Way can be seen though the sky is not fully dark.” Equipment: Canon EOS 6D DSLR camera, 14mm lens.

 The Milly Way and Venus

LuIS ARGERICH, ARGENTINA, 3 NOvEMbER 2013 Luis says: “Here’s a shot of the Milky Way at dusk with venus and the Moon just in the middle of it. Plenty of frefies decorate the scene. I like how the Milky Way can be seen though the sky is not fully dark.” Equipment: Canon EOS 6D DSLR camera, 14mm lens.

 The Pleiades TERRY HANCOCk AND RObERT FIELDS, MICHIGAN 13 NOvEMbER AND 28 DECEMbER 2013

 The Pleiades

Terry says: “Here is a collaborated image of the known as the Seven Sisters. While we continue with awful weather here Terry says: “Here is a collaborated image of the in Michigan it just makes sense to collaborate – this known as the Seven SARA WAGER, vALENCIA, SPAIN, NOvEMbER 2013 TO JANuARY 2014popular star cluster commonly timewith using different and cameras, but with  IC 410, IC 405, IC 417 and NGC 1931 Sisters. While we continue awful weather telescopes here a similar of view.” Sara says: “This mosaic took me two months to complete. It represents a total of in Michigan it just makes sense to feld collaborate – this SARA vALENCIA, SPAIN,and NOvEMbER 2013 TO time JANuARY using different telescopes and cameras, butmonochrome with 152WAGER, 30-minute exposures an integration of 762014 hours. The Flamingtime Star Equipment: QHY11S CCD camera, a similar feld of view.” Sara says: “This mosaic meshowing two months It represents a total Nebula, IC 405, istook aptly astoacomplete. bright orange fame. Theoffour targets all nestle STL 11000 monochrome CCD camera, Takahashi 152 30-minute exposures and an integration time of 76 hours. The Flaming Star Equipment: QHY11S monochrome CCD camera, neatly in the frame.” Epsilon-180ED telescope, Takahashi FSQ-106 telescope,

 IC 410, IC 405, IC 417 and NGC 1931

Nebula, IC 405, is aptly showing as a bright orange fame. The four targets all nestle neatly in the frame.” Equipment: Atik 460ExM CCD camera, Takahashi FSQ85 telescope,

Fast Reverse equatorial mount.Takahashi FSQ85 telescope, Avalon Linear Equipment: Atik 460ExM CCD camera, Fast Reverse equatorial mount.



TERRY HANCOCk ANDpopular RObERT star FIELDS, MICHIGAN cluster commonly 13 NOvEMbER AND 28 DECEMbER 2013

STL 11000 monochrome CCD camera, Takahashi

Paramount GT-1100S German equatorial mount, AstroAvalon Linear Epsilon-180ED telescope, Takahashi FSQ-106 telescope, Physicsequatorial AP900 German equatorial mount. Paramount GT-1100S German mount, AstroPhysics AP900 German equatorial mount.

HOTSHOTS APRIL 31

 Earthshine RICHARD bAILEY, bRAuNSTON, DECEMbER 2013 Richard says: “I managed to capture this image of earthshine just before the Moon set behind a tree. It was bright and the earthshine really stood out.” Equipment: Canon EOS 1000D DSLR camera, 80ED refractor.

HOTSHOTS APRIL 31

 Earthshine RICHARD bAILEY, bRAuNSTON, DECEMbER 2013 Richard says: “I managed to capture this image of earthshine just before the Moon set behind a tree. It was bright and the earthshine really stood out.” Equipment: Canon EOS 1000D DSLR camera, 80ED refractor.

 Sharpless 234 and 237

 NGC 6231

DAN CROWSON, MISSOuRI, 4 NOvEMbER 2013 Dan says: “Sharpless 234 and 237 are fairly bright emission nebulae located approximately 6,800 lightyears away in Auriga. Sharpless 234 is the nebula near the centre of the image; the cluster of stars is designated as Stock 8. Sharpless 237 is the smaller nebula on the left side of the image. It surrounds open cluster NGC 1931.”

HAREL bOREN, NAMIbIA, JuNE 2011

Equipment: Atik 383L+ mono CCD camera, APM 80/470 apo refractor,

Equipment: SbIG ST8300M CCD camera, Newtonian refector, Astro-Physics 1200GTO mount.

Sky-Watcher SharplessNEQ6 234 and 237 mount.

DAN CROWSON, MISSOuRI, 4 NOvEMbER 2013

 NGC 6231

Harel says: “Here’s an image, shot from the kalahari Desert in June 2011, which I have fnally come around to processing. It captures a colourful star feld comprising open cluster NGC 6231 through to the Prawn Nebula.”

Dan says: “Sharpless 234 and 237 are fairly bright emission nebulae located approximately 6,800 lightyears away in Auriga. Sharpless 234 is the nebula near the centre of the image; the cluster of stars is designated as Stock 8. Sharpless 237 is the smaller nebula on the left side of the image. It surrounds open cluster NGC 1931.”

HAREL bOREN, NAMIbIA, JuNE 2011

Equipment: Atik 383L+ mono CCD camera, APM 80/470 apo refractor, Sky-Watcher NEQ6 mount.

Equipment: SbIG ST8300M CCD camera, Newtonian refector, Astro-Physics 1200GTO mount.

Harel says: “Here’s an image, shot from the kalahari Desert in June 2011, which I have fnally come around to processing. It captures a colourful star feld comprising open cluster NGC 6231 through to the Prawn Nebula.”



32 HOTSHOTS APRIL

 The Flame and Horsehead Nebulae

 The Iris Nebula

PAuL GORDON, ESSEx, 5 JANuARY 2014 Paul says: “This image is the result of 12 fve-minute exposures at ISO 800.”

MARk GRIFFITH SWINDON 4 DECEMbER 2013

Equipment: Canon EOS 1000D DSLR camera, William Optics ZS80 telescope.

32 HOTSHOTS APRIL

 The Flame and Horsehead Nebulae

 The Iris Nebula

PAuL GORDON, ESSEx, 5 JANuARY 2014 Paul says: “This image is the result of 12 fve-minute exposures at ISO 800.” Equipment: Canon EOS 1000D DSLR camera, William Optics ZS80 telescope.

MARk GRIFFITH SWINDON 4 DECEMbER 2013

Mark says: “This was one of the frst deep-sky objects I ever tried to image – with poor results, far too diffcult for a beginner! This is my best image of this nebula yet.” Equipment: Atik 383L+ CCD camera, 8-inch Ritchey-Chrétien telescope, Sky-Watcher NEQ6 PRO mount.

Mark says: “This was

one of the frst deep-sky  The Andromeda Galaxy objects I ever tried to image – with poor results, GARY ANDERSON, GALLOWAY, 1 NOvEMbER 2013 far too diffcult for a

beginner! This isas myI always best Gary says: “This is my best image of M31 to date fnd processing galaxies of thisthe nebula diffcult. The detail in the dust lanes is image clear and coreyet.” is not blown out, giving a nice Equipment: Atik 383L+ natural look.” CCD camera, 8-inch

Equipment: Canon EOS 1000D DSLR camera, Sky-Watcher Ritchey-Chrétien telescope,80ED telescope. Sky-Watcher NEQ6 PRO mount.

 The Andromeda Galaxy GARY ANDERSON, GALLOWAY, 1 NOvEMbER 2013 Gary says: “This is my best image of M31 to date as I always fnd processing galaxies diffcult. The detail in the dust lanes is clear and the core is not blown out, giving a nice natural look.” Equipment: Canon EOS 1000D DSLR camera, Sky-Watcher 80ED telescope.

ENTER TO WIN A PRIzE! teamed up with the Widescreen Centre to offer the winner of next month’s best ENTER TO WINWe’ve A PRIzE! Hotshots image a fantastic prize. The winner will receive an Orion StarShoot Solar System We’ve teamed up with the Widescreen Centre todesigned offer the winner of next month’s Colour Imager Iv camera, for capturing sharpbest shots of Hotshots image a fantastic prize. The winner will receive an Orion StarShoot Solar System Colour Imager Iv camera, designed for capturing sharp shots 7935 of the Moon www.widescreen-centre.co.uk • 020 2580and planets.

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www.widescreen-centre.co.uk • 020 7935 2580 Email your pictures to us at [email protected] or enter online.

Email your pictures to us at [email protected] or enter online.



the Moon and planets.

It’s a planetary murder mystery: how did the once-wet Mars end up the dusty world it is today Sean Blair asks if we’re any closer to an answer It’s a planetary murder mystery: how did the once-wet Mars end up the dusty world it is today Sean Blair asks if we’re any closer to an answer

NASA/JPL-CALteCh/CorNeLL/ArizoNA StAte UNiv, NASA/JPL/texAS A&M/CorNeLL

O

Scant remains

planet, or three times higher than the cruising height of a commercial airliner. If there were suffcient concentrations to breathe, the air would be poisonous: more than 95 per cent carbon dioxide, plus nitrogen, argon and other trace gases. In 1946, astronomer Gerard Kuiper identifed carbon dioxide as Mars’s major

belief in the ‘canals’ that Percival Lowell – he who founded the Lowell Observatory in Arizona – was believed to have observed on the planet’s surface.

Scant remains Into the 1960s, ground-based spectrographic observations suggested that the Martian

mission, followed by Mariner 6 and 7 in 1969, charted a cratered Moon-like world. But a fuller picture was given in January 1972, from Mariner 9. The spacecraft actually attained Mars orbit the previous November, but its observations were delayed by a planet-wide dust storm – the >

It looks desolate now, but the It looks desolate now, but theevidence indicates that Mars was once much more pleasant evidence indicates that Mars was once much more pleasant

NASA/JPL-CALteCh/CorNeLL/ArizoNA StAte UNiv, NASA/JPL/texAS A&M/CorNeLL

O

n 8 April, Mars comes to its closest point to Earth in its two-year orbit. Observing that bright red world holds an added excitement, as we are looking at a planet we feel we know intimately. For years, Martian rovers have transmitted back views of a place remarkably like home, with morning mists and blue-tinted sunsets. It’s a beguiling illusion. If anyone were to step onto the surface unprotected, the thin atmosphere would cause the saliva n 8 April, Mars comes to its to boil away from their lips before they closest point to Earth in its blackedtwo-year out. Even if they managed to orbit. Observing Though the blue-tinted shout for help, they wouldholds be inaudible that bright red world an sunsets look homely, added excitement, as we looking from a distance ofare a few tensatofa metres. conditions on Mars planet we feel we know intimately. For years, are anything but Never forget Mars is an alien world Martian rovers have transmitted back – its single most alien element being views of a place remarkably like home, with atmospheric constituent. Previously it the ghostly remnant of sunsets. an atmosphere. atmosphere was extremely scant, morning mists and blue-tinted was assumed Mars had an Earth-like airillusion. pressure is lesswere than one something confrmed by radio science It’sSurface a beguiling If anyone to hundredth step onto the surface the level, atmosphere, because of the ‘clouds’ so that ofunprotected, Earth’s at sea experiments during Mariner 4’s twothin atmosphere would cause the saliva frequently sighted, as well as a stubborn equivalent to an altitude of 35km on our day fyby of the planet in July 1965. That to boil away from their lips before they belief in the ‘canals’ that Percival Lowell planet, or three times higher than the mission, followed by Mariner 6 and 7 blacked out. Even if they managed to Though the blue-tinted – he who founded the Lowell Observatory cruising height of a commercial in 1969, charted a cratered Moon-like shout for help, they would be inaudible airliner. sunsets look homely, from a distance of suffcient a few tens ofconcentrations metres. in Arizona – was believed to have If there were to world. But a fuller picture was given conditions on Mars are anything but Never forget Mars is an alien world observed on the planet’s surface. breathe, the air would be poisonous: more in January 1972, from Mariner 9. The – its single most alien element being than 95 per cent carbon dioxide, plus spacecraft actually attained Mars orbit the atmospheric constituent. Previously it the ghostly remnant of an atmosphere. atmosphere was extremely scant, nitrogen, argon and trace gases. previous November, but its observations was assumed Mars had an Earth-like Surface air pressure is lessother than one something confrmed by radio science In 1946, were delayed theof1960s, ground-based spectrographic atmosphere, Into because the ‘clouds’ so hundredth that astronomer of Earth’s at seaGerard level, Kuiper experiments during Mariner 4’s two- by a planet-wide dust frequently sighted, as well as suggested a stubborn that day equivalent to an altitudedioxide of 35km on of the planet storm in July 1965. identifed carbon as our Mars’s major – theThat observations thefyby Martian >

36

> true nature of the ‘clouds’. Once the dust settled, images, but calibration checks confrmed airborne Þ Today we see dried-up dust actually left it reddish. Mariner 9 revealed a startlingly Earth-like world, lakes; 3.5 billion years ago, we may have seen Fast forward to today and two new robotic with layered ice caps, cirrus clouds, and dried-up something more like this detectives are en route to join the rovers and food plains and riverbeds. orbiters already at Mars. India’s Mangalyaan, Around four billion years ago, Mars’s atmosphere offcially the Mars Orbiter Mission (MOM), weighs was still dense enough to sustain liquid water on in at more than a tonne including fuel, although the surface – the atmosphere was probably denser only 15kg of that mass is scientifc payload. There than Earth’s, because it receives only less than half > true images, but calibration confrmed airborne the ‘clouds’. Once dust settled, arechecks fve instruments aboard, including two focused the nature energyof from the Sun asthe Earth does, and Þthe Sunwe see dried-up Today dust actually left it reddish. Mariner 9 revealed a startlingly Earth-like world, lakes; 3.5 billion years on the detection of trace gases deuterium and shone 30 per cent less brightly at the time. So Mars ago, we may have seen Fast forward to today and two new robotic with layered ice caps, cirrus clouds, and dried-up methane. But for the new space-faring nation of exploration became a kind of murder mystery: why something more like this detectives are en route to join the rovers and food plains and riverbeds. India, MOM’s major achievement would simply be did thisfour initially hospitable planet perish? How was orbiters already at Mars. India’s Mangalyaan, Around billion years ago, Mars’s atmosphere achieving Mars orbital insertion, which is scheduled offcially the Mars Orbiter Mission (MOM), weighs was dense enough to sustain liquid water on itsstill atmosphere stolen away? in at more than a tonne including fuel, although the surface – the atmosphere was probably denser for September. Any useful science would be a bonus. The 1976 Viking missions flled in details of only 15kg of that mass is scientifc payload. There than Earth’s, because it receives only less than half the murder scene – including in-situ atmospheric instruments aboard, including two focused the energy from the Sun as Earth does, and the Sun þ Mariner 9,arethefvefrst craft measurements, researchers were on the detection of trace gases deuterium and shone 30 per cent less though brightly atViking the time. So Mars to enter Martian orbit, themselves beguiled Mars’smystery: Earth-like Hopes are higher for of NASA’s MAVEN (Mars methane. But for the new space-faring nation exploration became a kind by of murder why appearance. revealed a slew of EarthMOM’s majorAtmosphere achievement would be Evolution), also due didThe this thin initially planetblue perish? How waslander skyhospitable was graded in initial and simply Volatile like surface India, features achieving Mars orbital which scheduled its atmosphere stolen away? toinsertion, reach the RedisPlanet in September. This vanfor September. Any useful science would be a bonus. The 1976 Viking missions flled in details of sized spacecraft will focus on particles escaping the murder scene – including in-situ atmospheric þ Mariner 9, the frst craft from Mars right now, not just by monitoring measurements, though Viking researchers were The plot thickens to enter Martian orbit, upper atmosphere, but actually descending themselves beguiled by Mars’s Earth-like appearance. revealed a slew of EarthHopes are higher forthe NASA’s MAVEN (Mars The thin sky was graded blue in initial lander Atmosphere and Volatile Evolution), also due into it once per orbit. like surface features to reach the Red Planet “We’re in September. This vanapplying previous experience of sized spacecraft will focus on particles escaping aerobraking spacecraft to go down as low as 150km, from Mars right now, not just by monitoring which is below the altitude that escape occurs,” says the upper atmosphere, but actually descending into it once per orbit.Bruce Javovsky, MAVEN’s principal investigator. “We’re applying previous of “Thenexperience we’ll be performing fve ‘deep dips’ during aerobraking spacecraft to go down as low as 150km, our year-long mission where we go even lower, to which is below the altitude that escape occurs,” says 125km, to sample the entire stratifed column of Bruce Javovsky, MAVEN’s principal investigator. the upper atmosphere. “Then we’ll be performing fve ‘deep dips’ duringThe Martian atmosphere our year-long mission we go even lower, is where tenuous enough thattowe aren’t in danger, but 125km, to sample thesome entirehigh-power stratifed column of instruments will be switched the upper atmosphere. The Martian atmosphere off to avoid damage. Our gull-design solar is tenuous enough that we aren’t in danger, but wings help ensure aerodynamic stability. some high-power instruments will be switched

The plot thickens

UNiverSitY)/MiKe WoLff (SPACe SCieNCe iNStitUte) ANd NASA, NASA/goddArd

KeeS veeNeNBoS/SCieNCe Photo LiBrArY, NASA/JPL-CALteCh x 3, NASA, NASA/JAMeS BeLL (CorNeLL UNiv.)/MiChAeL WoLff KeeSiNSt.) veeNeNBoS/SCieNCe Photo LiBrArY, NASA/JPL-CALteCh x 3, of NASA, NASA/JAMeS BeLL (CorNeLL UNiv.)/MiChAeL WoLff (SPACe SCieNCe ANd the hUBBLe heritAge teAM (StSCi/AUrA), Steve Lee (UNiverSitY CoLorAdo)/JiM BeLL (CorNeLL (SPACeWoLff SCieNCe iNSt.) ANd the hUBBLe heritAge teAM (StSCi/AUrA), Steve Lee (UNiverSitY of CoLorAdo)/JiM BeLL (CorNeLL UNiverSitY)/MiKe (SPACe SCieNCe iNStitUte) ANd NASA, NASA/goddArd

36

off to avoid damage. Our gull-design solar wings help ensure aerodynamic stability.



mars’s atmosphere april 37

seasonal Changes Mars has terrestrial-style seasons, encouraged by its Earth-like axial tilt. Its highly eccentric (very ‘uncircular’) orbit means its distance from the Sun varies over the course of a 687-day Martian year by some 42 million km  shiftinG ice caps

Mars’s two polar caps undergo dramatic seasonal shifts. During the darkness of winter mars’s atmosphere april 37 dioxide freezes out of the atmospheric carbon air, falling as snow. The effect is greatest when Mars is farthest from the Sun; atmospheric pressure drops by a third. The seasonal southern cap is larger (extending more than halfway to the equator) because the Martian seasons are uneven: the southern winter lasts Mars has terrestrial-style seasons, encouraged by its Earth-like axial tilt. Its highly eccentric (very ‘uncircular’) longer,km coinciding with Mars’s aphelion, its orbit means its distance fromJUNE the Sun varies over the course of a 687-day Martian year by some 42 million SEptEMbEr maximum distance from the Sun. The southern 2001 2001 summer is correspondingly short, but also  shiftinG ice caps warmer, with 40 per cent more sunlight. This Mars’s two polar caps undergo dramatic seasonal shifts. During the darkness of winter means much of the south pole’s 1km-thick atmospheric carbon dioxide freezes out of the carbon dioxide layer is vaporised, leaving air, falling as snow. The effect is greatest when  Giant dust storms 3km-thick pole of water ice behind. Mars is farthest from theaSun; atmospheric It is when Mars draws closest to the Sun that the greatest planetary-scale dustpressure storms drops occur. by a third. The seasonal Mars’s wispy atmosphere is unable to transfer heat effciently, causing regional temperature southern cap is larger (extending more than to the equator) because the Martian differences of up to 30°C to drive winds above 100km/h, lifting thin dust thathalfway blankets whole seasons are uneven: regions or the entire planet. Summer dust devils are also common. Any astronaut would feel the southern winter lasts longer, coinciding with Mars’s aphelion, its JUNE SEptEMbEr only a mild breeze, although dust storms might also generate worrying static electric ‘e-felds’. maximum distance from the Sun. The southern

seasonal Changes

2001

2001

summer is correspondingly short, but also

warmer, with 40 per cent more sunlight. This  equatorial streaks means much of the south pole’s 1km-thick

The sharp-eyed Mars Reconnaissance carbon dioxide layer is vaporised, leaving Orbiter has spotted surface streaks  Giant dust storms a 3km-thick pole of water ice behind. It is when Mars draws closest to the Sun that the greatest planetary-scale dust stormsterritory. occur. Extending around equatorial Mars’s wispy atmosphere is unable to transfer heat effciently,downhill, causing regional these temperature dark streaks appear at differences of up to 30°C to drive winds above 100km/h, lifting thin dust that blankets whole the warmest time of year, fading as the regions or the entire planet. Summer dust devils are also common. Any astronaut would feel planet grows cooler, only to return the only a mild breeze, although dust storms might also generate worrying static electric ‘e-felds’. following summer. Flowing liquid water is the most likely explanation, probably  equatorial streaks The sharp-eyed Mars Reconnaissance originating from buried permafrost with Orbiter has spotted surface streaks salt deposits acting as a kind of around equatorial territory. Extending antifreeze. This 2013 discovery builds downhill, these dark streaks appear at on earlier fnds of freshly formed the warmest time of year, fading as apparent the down craters planet grows gullies cooler, only to return the and slopes. following summer. Flowing liquid water is the most likely explanation, probably originating from buried permafrost with “What we want to understand aresalt thedeposits processes acting as a kind of MAVEN’s bird-like ‘gull antifreeze. This 2013 builds occurring in the upper atmosphere today. What is discovery wings’ will help it swoop earlier fnds of apparent freshly formed its composition and loss rate? How isonthis affected over the Martian surface gullies down craters and slopes.

low

by incoming solar energy rates?” MAVEN will build on the atmospheric “What we want to understand are the processes observations of ESA’s Mars Express, which has MAVEN’s bird-like ‘gull occurring in the upper atmosphere today. What is wings’ will help it swoop low been in orbit around Mars for a decade, sampling its composition and loss rate? How is this affected over the Martian surface by current incomingatmospheric solar energy rates?” loss rates. The ESA probe MAVEN willMars’s build onunique the atmospheric identifed equatorial aurora, a result observations of ESA’s Mars Express, which has of solar wind particles encountering the magnetised been in orbit around Mars for a decade, sampling remnants of theloss planet’s now-lost magnetic feld. current atmospheric rates. The ESA probe These Mars’s cause unique ultraviolet glows thataare sadly invisible identifed equatorial aurora, result of to solar wind particles human eyes. encountering the magnetised remnants the planet’s now-lostfeld magnetic The of missing magnetic is thefeld. frst suspect in These cause ultraviolet glows that are sadly invisible the murder mystery. It’s a symptom of Mars’s small to human eyes. stature: only half Earth’s size and onlyin11 per cent > The missing magnetic feld is the frst suspect the murder mystery. It’s a symptom of Mars’s small stature: only half Earth’s size and only 11 per cent >



38

> its mass with about 38 per cent terrestrial gravity. Mars’s smaller molten core would have cooled rapidly, shutting down its protective magnetic feld. At high altitude, gases are split apart by ultraviolet radiation into electrically charged ions, which are then accelerated to escape velocity by the solar wind. Like a slow-motion comet, Mars’s atmosphere is being very gradually blown away. The snag is that Mars Express suggests that escape susceptibility is 38limited to lightweight atoms such as hydrogen or oxygen ions – not heavier carbon dioxide, which has always formed most of the atmosphere. > its mass with about 38 per cent terrestrial gravity. Suspect two is the possibility that early Mars’s Mars’s smaller molten core would have cooled warmshutting wetness sparked its doom. Carbon rapidly, down its protective magnetic feld. was extracted the atmosphere At steadily high altitude, gases arefrom split apart by ultraviolet by damp radiation electrically charged which are Earth is silicateinto rocks to form solidions, carbonates. then accelerated to escape velocity by the only saved a similar fate by platesolar tectonics regularly wind. Like a slow-motion comet, Mars’s atmosphere recycling the surface to liberate stored carbon back is being very gradually blown away. The snag is that into the atmosphere– but, susceptibility again, Marsisis too small Mars Express suggests that escape

Data published in 2009 revealed localised methane, possibly from an active source

Data published in 2009 revealed localised methane, possibly from an active source

0

5 10 15 20 25 Methane concentration (parts per billion)

30

MEthaNE rElEaSE: NorthErN SUMMEr 2003

limited to lightweight atoms such as hydrogen or oxygen ions – not heavier carbon dioxide, which has always formed most of the atmosphere. Suspect two is the possibility that early Mars’s warm wetness sparked its doom. Carbon was steadily extracted from the atmosphere by damp The methane sensor on India’s Mars silicate rocks to form solid carbonates. Earth is Orbiter Mission (MOM) aims to solve only saved a similar fate by plate tectonics regularly a decade-long mystery. It will recycling the surface toscientifc liberate stored carbon back be put into action as MOM rises to its into the atmosphere– but, again, Mars is too small

for plate tectonics to take hold. The problem here is that the vast amount of carbonate deposits this implies has still to be found. Suspect three is suggested by the planet’s heavily 0 5 10 15 20 25 30 methane originates mainly from cratered surface – and the event due to happen this Methane concentration biological processes, or else volcanoes. October. towards us at 56km/s, Comet (parts perHeading billion) But last year NASA’s Curiosity rover C/2013 A1 Siding Spring is projected to pass within MEthaNE rElEaSE: NorthErN SUMMEr 2003 analysed local air samples, failing 41,300km of Mars. Both MAVEN and Mars Express farthest distance from Mars, around to fnd any methane at all. 80,000km – at this distance MOM will Had the methane never been there have The their orbitshere altered to shelter them behind for plate tectonics to will take hold. problem move relatively slowly compared to Mars at all, or is some unknown phenomenon is that the vast amount of carbonate depositsapproach this Mars during closest – fearing cometary below, allowing for long-exposure removing it from the atmosphere impliesat hasa still to bedust found. impacts. They will use their high-gain antennas searches for the spectral fngerprints rate hundreds of times faster Suspect than three is suggested by the planet’s heavily The methane sensor on India’s Mars methane originates mainly from as shields and angle their solar arrays edge-on. of this colourless, odourless gas. terrestrial methane? Proposed cratered surface – and the event due to happen this Orbiter Mission (MOM) aims to solve biological processes, or else volcanoes. Such encounters In 2004, Mars mystery. ExpressIt and include October. Heading towards us close at 56km/s, Comet are rare today, but as late a decade-long scientifc will But last yearmechanisms NASA’s Curiosity rover dust storm as 3.8 billion years ago the Solar System remained C/2013 A1 Siding Spring is projected to pass within ground-based observatories detected ‘electric felds’, soil superoxides and be put into action as MOM rises to its analysed local air samples, failing 41,300km of Mars. Both MAVEN and Mars Express farthest fromof Mars, aroundgas on to fnd any methane at all. smalldistance amounts methane methane-eating bacteria. Hopefully, a violent neighbourhood. The Martian atmosphere 80,000km – at this distance Had the methane been fnd therethe answer; will have altered to shelter them behind Mars, averaging 10 MOM parts will per billion MOM never will help if their orbitsmight have been expelled to space by repeated move relatively slowly compared to Mars at all, or is some unknown phenomenon Mars during closest approach – fearing cometary but rising as high as 30 at times (by not, Europe’s ExoMars Trace Gas below, allowing for long-exposure removing it from the atmosphere at a impacts, also triggering catastrophic foods by impacts. comparison, Earth’sfngerprints atmosphere contains Orbiter due than for launch indust 2016 and They will use their high-gain antennas searches for the spectral rate hundreds of times–faster temporarily melting permafrost. shields and angle their solar arrays edge-on. 1,800 parts odourless per billion). possessing parts per trillionassensitivity, of this colourless, gas. It was an terrestrial methane? Proposed

The hunT for methane

NASA/JPL-CALteCh, NASA/treNt SChiNdLer, iNdiA SPACe reSeArCh orgANiSAtioN, NASA/JPL-CALteCh, NASA/treNt SChiNdLer, iNdiA SPACe reSeArCh NASA/JPL-CALteCh/CorNeLL UNiverSitY, NASA/JPL/MSSS, eSA–d. dUCroS

orgANiSAtioN, NASA/JPL-CALteCh/CorNeLL UNiverSitY, NASA/JPL/MSSS, eSA–d. dUCroS

The hunT for methane

Inexciting 2004, Mars Express because and mechanisms should include dust storm to do so. discovery terrestrial be able ground-based observatories detected ‘electric felds’, soil superoxides and small amounts of methane gas on methane-eating bacteria. Hopefully, Mars,MOM, averaging 10 parts in per billion MOM will help fnd the answer; if launched but rising as high as2013, 30 at will timeslook (by not, Europe’s ExoMars Trace Gas November comparison, Earth’s atmosphere contains Orbiter – due for launch in 2016 and for methane spectrally 1,800 parts per billion). It was an possessing parts per trillion sensitivity, exciting discovery because terrestrial should be able to do so. MOM, launched in November 2013, will look for methane spectrally



Such close encounters are rare today, but as late as 3.8 billion years ago the Solar System remained a violent neighbourhood. The Martian atmosphere How lively is today’s Martian atmosphere? might have been expelled to space by repeated Memorably, came up with his impacts, also triggering catastrophicJames foods Lovelock by theory after contrasting Earth’s life-driven temporarily melting Gaia permafrost.

The methane mystery

atmosphere with static Mars. But how static is it

The methanereally? mystery In 2004 both Mars Express and ground-

How lively is today’s Martian atmosphere? based observatories detected short-lived plumes Memorably, James Lovelock came up with his of methane over various Martian regions. The Gaia theory after contrasting Earth’s life-driven atmosphere with static Mars. Butremains how statichugely is it discovery controversial – on Earth really? In 2004 both it Mars Express and groundtakes hundreds of years for photochemistry to based observatories detected short-lived plumes remove methane from the atmosphere. Then last of methane over various Martian regions. The year controversial NASA’s Curiosity rover failed to detect any discovery remains hugely – on Earth Marsfor methane whatsoever, although terrestrial it takes hundreds of years photochemistry to remove methane from the atmosphere. monitoring Then last spectrographic goes on. year NASA’s Curiosity rover failed to detect any “Most of the time we don’t detect anything; it’s Mars methane whatsoever, although terrestrial only released spasmodically,” says Michael Mumma spectrographic monitoring goes on. Exploration Division at NASA’s “Most of the time of we the don’tSolar detectSystem anything; it’s only released spasmodically,” says Michael Mumma of the Solar System Exploration Division at NASA’s

mars’s atmosphere april 39

water on mars counterparts confrmed trace levels of The number of times mainstream headline atmospheric water vapour. More recently, writers have hailed the discovery of ‘Water Mars Express has shown water vapour can on Mars!’ must be well into double digits be ‘supersaturated’ when Mars is at its coldest, by now. We’ve known Martian water once making it wetter than previously thought existed since 1969, when Mariner 9 (although still with 10,000 times charted drainage channels less water vapour than atmosphere Earth). – apparent evidence of a mars’s april 39 Looking at the ground, warm, wet early Mars. radar instruments proved The mystery of these that the Martian poles features is that they Þ Haematite ‘blueberries’ could only have contain enough water appear quite formed in water, providing more evidence ice to food the entire abruptly in the surface to a depth of landscape, rather that can only be formed in water, suggesting counterparts confrmed trace levels of Thethan number times mainstream headline 11m and established by ofthe the equatorial Meridian Planum plain was atmospheric water vapour. More recently, writers have hailed the discovery of ‘Water that subsurface ice gradual once hot springs or even an acid-tinged Mars Express has shown water vapour can on Mars!’ must be well into double digits extends down to midof Martian water once lake. Last year Curiosity went one better, be ‘supersaturated’ when Mars is at its coldest, by accumulation now. We’ve known riversince systems. TheseMariner 9 establishing through streambed clay deposits making it wetter than previously thought latitudes. This ice has existed 1969, when (although still with 10,000 times charted drainage channels been seen directly by might have been that 3.5 billion years ago Gale Crater housed less water vapour than Earth). – apparent evidence of a the Mars Reconnaissance comparatively a lake with water ‘good enough to drink’. Þ Meteorite impacts Looking at the ground, warm, wet early Mars. Orbiter, following asteroid brief-lived phenomena, Spare a thought also for the oft-neglected radar instruments proved The mystery of these revealed hidden deposits impacts uncovering the based on they transitory 2008 Phoenix lander. Although it was that the Martian poles features is that Þ Haematite ‘blueberries’ couldMars only have of water ice contain enough water of water appear quite from geological bright-white which meltwater formed ice, in water, providing more evidence immobile, its thrusters cleared dust to reveal iceeventually to food the fades. entire Mapping has also abruptly in the activity or meteorite impacts. bright water ice beneath, and apparent surface to a depth of landscape, rather thatlowlands can only beare formed in water, suggesting demonstrated Mars’s northern The 1970s Viking landers recorded liquid droplets were recorded fowing along 11m and established than by the the equatorial Meridian Planum plain was suffciently fat to have formed a shallow ocean. early morning water-ice mist and frost struts – potentially the historic that subsurface ice gradual once hot springs or evenits anlanding acid-tinged NASA’sextends roversdown havetogathered in-situ evidence: – although frst detection midaccumulation of coatings are only a fraction lake. Last year Curiosity went one better, of liquid Martian water – kept latitudes. This ice has river These thick – while their orbital establishing through streambed clay deposits Opportunity discovered haematite ‘blueberries’ ofsystems. a millimetre from freezing by perchlorate salts.

water on mars

been seen directly by might have been the Mars Reconnaissance comparatively Þ Meteorite impacts Orbiter, following asteroid brief-lived phenomena, revealed hidden deposits impacts uncovering the based on transitory Goddard Space Flight Center. of “We have water ice bright-white of water ice, which meltwater from geological campaigns at three observatories – ESO’s eventually fades. Mapping has also activity or meteorite impacts. The 1970s landers in recorded Very LargeViking Telescope Chile, Keck demonstrated Mars’s northern lowlands are suffciently fat to have formed a shallow ocean. early morning water-ice mist and frost NASA’s Infrared –and although coatings are onlyTelescope, a fraction both NASA’s rovers have gathered in-situ evidence: of millimetre Adaptive thick – whileoptics their orbital inaHawaii. provide Opportunity discovered haematite ‘blueberries’

that 3.5 billion years ago Gale Crater housed a lake with water ‘good enough to drink’. Spare a thought also for the oft-neglected 2008 Mars Phoenix lander.plumes Althoughcompared it was sporadic to past seasonal immobile, its thrusters cleared dust to reveal averages. And a new ESA mission, the bright water ice beneath, and apparent liquid droplets were recorded fowingTrace along Gas Orbiter, joins the ExoMars its landing struts – potentially the historic search 2016. It will also measure frst detection of liquid Martian waterin – kept from freezing by perchlorate salts.broader trace gas isotope ratios

high angular resolution no to gain insight into the matter the distance. The real atmosphere’s past Goddard Space Flight Center. “We have sporadic plumes compared to past seasonal issue is at wethree require a large – ESO’s rates of change. campaigns observatories averages. And a new ESA mission, the Doppler shift to take the Mars “This 2016 mission Very Large Telescope in Chile, Keck ExoMars Trace Gas Orbiter, joins the and NASA’s Infrared Telescope, search in 2016. It will also measure spectral lines away from both should give us some pretty in Earth’s Hawaii. Adaptive provide at broader trace gas isotope ratios defnitive information,” says lines. Sooptics we observe high angular resolution no to gain insight into the times when Mars has a high Mumma. “What we don’t have matter the distance. The real atmosphere’s past line of sight velocity relative to yet is an additional destruction issue is we require a large rates of change. Earthshift – intoJanuary was moving mechanism for the methane to be Doppler take theitMars “This 2016 mission spectral lines away from should give us some pretty towards Earth at about 17 km/s disappearing, but there’s much we Earth’s lines. So we observe at defnitive information,” says about Mars and that’s – leaving us confdent we’re not don’t know times when Mars has a high Mumma. “What we don’t have mistaking terrestrial methane. why we continue to send spacecraft line of sight velocity relative to yet is an additional destruction “We’re also looking for deuterium, there. It’stoan Earth – in January it was moving mechanism for the methane beexciting time; within a towards Earth at aboutof17water. km/s If subsurface disappearing, but there’s we much we have an answer.” S a heavy isotope decade should – leaving us confdent not seasonally by don’t know about Mars and that’s methane is beingwe’re released mistaking terrestrial methane. why we continue to send spacecraft permafrost melting, then ancient water vapour “We’re also looking for deuterium, there. It’s an exciting time; within a ABOUT THE WRITER might escape too. This would possess a much a heavy isotope of water. If subsurface decade we should have an answer.” S Sean Blair is a science and lowerisdeuterium-water ratiobythan surface water methane being released seasonally Þ The ExoMars orbiter technology journalist. A former permafrost then ancientescape water vapour subject melting, to atmospheric of lighter isotopes. will look for clues on how ABOUT THE WRITER guinness World records might would possess a muchthan methane.” fast Mars’s atmosphere Andescape watertoo. is This much easier to detect Sean Blair is a science and researcher, he now edits eSA’s lower deuterium-water ratio than surface water Þ The ExoMars has orbiter altered over time Mars Express is meanwhile commencing technology journalist. A former space engineering website. subject to atmospheric escape of lighter isotopes. will look for clues on how guinness World records localised methane searches to try and catch fast Mars’s atmosphere And water is much easier to detect than methane.” Mars Express is meanwhile commencing localised methane searches to try and catch

has altered over time

researcher, he now edits eSA’s space engineering website.



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Mars is an alluring target because of how Earth-like many of its surface features are

Mars is an alluring target because of how Earth-like many of its surface features are

thinkstock

thinkstock

Mars Mars

at oPPosition at oPPosition Martin Lewis presents the ultimate guide to observing Martin Lewis presents the ultimate guide to observing the Red Planet, its top sights, plus his imaging tips the Red Planet, its top sights, plus his imaging tips

42

M

ars, that most captivating of planets, visits our evening sky this spring, reaching opposition in the constellation of Virgo on 8 April. The Red Planet is the only world in the Solar System that readily reveals details of its rocky surface when viewed from Earth and this, together with a multitude of seasonal changes, makes it a fascinating planet to observe. At opposition, when Mars is at its nearest, 42it will shine as a ruddy beacon beckoning you to view, but be warned, the Mars observing season is relatively short. Once April is over, the planet appears that most captivating of planets, to shrink ars, noticeably from week to week and by midvisits our evening sky this spring, August it reaching is all but lost, low evening twilight. opposition in in thethe constellation Aroundofopposition, Mars Virgo on 8 April. Thewill Redshine Planet at is mag. the–1.5, only world in the Solar System that readily making it just as brilliant as the brightest reveals its rocky when viewed star details in theofnight sky.surface The planet’s reddish colour from Earth and this, together with a multitude of will be immediately apparent to the naked eye seasonal changes, makes it a fascinating planet to and even more obvious in binoculars. Even at observe. At opposition, when Mars is at its nearest, opposition, however, it beckoning is unlikely you it will shine as a ruddy beacon you to will see view, be warned, the Mars observing season anybut surface features in binoculars: foristhat you relatively short. Once April is over, the planet appears will need a telescope. to shrink noticeably from week to week and by midWhen through the eyepiece August it is allyou but look lost, low in the evening twilight.of your telescope what details onshine Marsatmight Around opposition, Mars will mag. you be able to –1.5, making it just as brilliant as the brightest see? The answer to this depends on the size of your star in the night sky. The planet’s reddish colour telescope and how steady your skies are, but also will be immediately apparent to the naked eye farthest point from the Sun; at best the planet was on the planet’s apparent size and its height above and even more obvious in binoculars. Even at only 14 arcseconds across. However, to make up your horizon. to Mars’s elliptical opposition, however,Due it is unlikely younoticeably will see for its small size, the planet was well north of the itsfeatures size atinopposition canthat vary anyorbit, surface binoculars: for youby nearly a will need aof telescope. celestial equator. This meant it was quite high in factor two. At its closest, Mars can be as large When you look through the eyepiece of your our skies, helping us to see good surface details. as 25 arcseconds across, over half the apparent telescope what details on Mars might you be able to During this year’s opposition it will be larger, at diameter of the gas giant Jupiter. Unfortunately for see? The answer to this depends on the size of your 15.1 arcseconds across, but this will be offset by northern hemisphere these telescope and how steady yourobservers, skies are, but also very close the fact thatatMars will be about lowerstriking in thealbedo farthest the Sun; best the planet was 15° oppositions when is point from onMars the planet’s apparent always size and occur its height abovethe planet Þ Mars’s features are easily only 14 arcseconds across. However, to make up your horizon. Due to Mars’s noticeably elliptical sky with a maximum altitude of only 33°. Despite far south in the sky. Frustratingly for us in the seen, especially through for its small size, the planet was well north of the orbit, its size at opposition can vary by nearly a this, on nights of steady seeing there should UK, this means that it then never gets particularly a large telescope celestial equator. This meant it was quite high in factor of two. At its closest, Mars can be as large still be plenty of details to see on the surface high in our skies. A low altitude means the view our skies, helping us to see good surface details. as 25 arcseconds across, over half the apparent with your telescope. is much more affected by Unfortunately atmosphericforturbulence During this year’s opposition it will be larger, at diameter of the gas giant Jupiter. 15.1 arcseconds across, but this will be offset by northern hemisphere very close and this softens observers, the view,these blurring fne surface Mars oppositions always occur when the the planet is of the fact that Mars will be about 15° lower in the detail, and stopping us making most sky with a maximum altitude of only 33°. Despite far south in the sky. Frustratingly for us in the these close approaches. Through a telescope with a 4-inch or smaller this, on nights of steady seeing there should UK, this means that it then never gets particularly The previous opposition in 2012 was certainly aperture with high magnifcation, you should still be plenty of details toand see on the surface high in our skies. A low altitude means the view not amore closeaffected one. Mars was nearly at aphelion,with its your telescope. see the reddish disc and the small brilliantly white is much by atmospheric turbulence

M

Þ Mars’s striking albedo features are easily seen, especially through a large telescope

Scope size matters

damian peach, martin lewis, chart by pete lawrence, steve marsh

damian peach, martin lewis, chart by pete lawrence, steve marsh

and this softens the view, blurring fne surface detail, and stopping us making the most of these close approaches. Eridania The previous opposition in 2012 was certainly Ausonia not a close one. Mars was nearly at aphelion, its

Mare Cimmerium Eridania

Scope size matters Hadriacum

Mare

Hadriacum

Amazonis Cimmerium

Amazonis

Mare Serpentis

Mare Tyrrhenum Mare

Ausonia

Syrtis Mare Minor Tyrrhenum Syrtis Minor

Elysium

Argyre

Through a telescope with a 4-inch or smaller aperture and with high magnifcation, you should Maredisc and the small brilliantly white see the reddish

Sinus Sinus Sabaeus Mare Erythraeum Meridiani

Mare Serpentis

Syrtis Sinus MajorSabaeus Arabia

Syrtis Major Arabia

Solis Lacus

Mare Erythraeum

Argyre

Aurorae Sinus Solis Lacus

Aurorae Sinus

Sinus Meridiani

Eden

Tharsis Tharsis

Niliacus Lacus

Eden

Elysium

E

Utopia

E

Utopia

N N



Niliacus Lacus Mare Acidalium Baltia

Mare Acidalium Arcadia

Baltia

Arcadia

mars at opposition april 43

BOÖTES

Arcturus

VIRGO SERPENS CAPUT

Porrima 30 Apr mars at opposition april 43 1 Apr

BOÖTES

CRATER

Mars

Arcturus

Spica VIRGO

LIBRA

SERPENS CAPUT OPHIUCHUS

Porrima 30 Apr

Saturn

1 Apr

CRATER

Mars

CORVUS

HYDRA

Spica

LIBRA OPHIUCHUS

SE

S Saturn

CORVUS

Þ Approximate sky orientation for 1, 15 and 30 April at 01:00 BST, 00:00 BST and 23:00 BST respectively

north polar ice cap, which is tilted towards us at HYDRA the moment. You should also see one or two of the more prominent darker features on the surface such as the wedge-shaped region known as the Syrtis SE S Major, or the Mare Acidalium, a large shield-shaped darker region in the northern hemisphere. These dark features generally north polar icealbedo cap, which is tiltedare towards us at areas where the Þ Approximate sky Martian wind has swept away most orientation for 1, 15 and 30 the moment. You should also see one or two of the of the lighter, April at 01:00 BST, 00:00 BST more prominent features the surfacethe such reddish,darker desert dust,onrevealing darker rocky and 23:00 BST respectively as the wedge-shaped region known as thefeatures Syrtis change subtly surface underneath. Such Major, or the Mare Acidalium, a large shield-shaped from season to season as the dust is moved around darker region in the northern hemisphere. These þ Just like the Moon, Mars butfeatures it is unlikely you will much dark albedo are generally areassee where the sign of these is covered in recognisable in aaway small telescope. wind has swept most of the lighter, named surface featuresMartian variations reddish, desert dust, revealing the darker Telescopes with 6-inch orrocky larger apertures surface underneath. features can revealSuch much morechange detailsubtly on the planet, from season to season as the dust is moved around þ Just like the Moon, Mars particularly on nights of very good seeing. This but it is unlikely you will see much sign of these is covered in recognisable includes obvious seasonal effects that stem variations in a smallthe telescope. Þ Attaching a Wratten #25 red flter to your eyepiece named surface features Mare or larger apertures fromwith the6-inch fact that Mars’s axis is tilted to a similar SirenumTelescopes can help to reveal less-obvious dark albedo features can reveal much more detail onMartian the planet, degree to Earth’s. seasons are always one particularly on nights of very good seeing. This ahead of those on Earth, meaning Mars’s northern includes the obvious seasonal effects that stem Mare Þ Attaching a Wratten #25 red flter to your eyepiece areas identifed on the accompanying albedo map, isaxis nowis moving Amazonisfrom thehemisphere fact that Mars’s tilted to a towards similar mid-summer. Sirenum can help to reveal less-obvious dark albedo features Pavonis shown left. A red flter (Wratten number #25), means thatseasons the north polar cap, which is tilted degree toThis Earth’s. Martian are always one Lacus ahead oftowards those on Earth, meaning Mars’s northern screwed into the eyepiece or held between your the Sun and Earth, is shrinking. Through areas identifed on the accompanying albedo map, hemisphere is now moving towards mid-summer. Amazonis eye and the eyepiece, may help you pick out the your telescope you may be able to see the shape as Pavonis shown left. A red flter (Wratten number #25), This means that the north polar cap, which is tilted Lacus more diffcult of these albedo features. The flter well as the size of the polar cap and possibly detect screwed into the eyepiece or held between your towards the Sun and Earth, is shrinking. Through theout contrast by darkening the features a darker snows Olympus eye and the eyepiece,will may increase help you pick the your telescope you band may bewhere able to the see the shapehave as retreated relative to the redder background. If the seeing around the pole. more diffcult of these albedo features. The flter well as the size of the polar cap and possibly detect Mons will increase the contrast by darkening the features a darker band where the snows have retreated Olympus is good don’t be afraid to increase the eyepiece The dark albedo surface features are also better relative to the redder background. If the seeing around the pole. Mons magnifcation to pull out more detail. The best seen in larger telescopes. Depending on which side is good don’t be afraid to increase the eyepiece The dark albedo surface features are also better is todetail. experiment is facing Earth, exotic sounding features like the magnifcation to pullthing out more The best – you’ll know that you’ve seen in larger telescopes. Depending on which side gone tooknow far when the detail starts to blur out Sebaeus, Utopia and like Aurorae Sinus may thing is tobe experiment – you’ll that you’ve is facing Sinus Earth, exotic sounding features the Scandia gone too far when the detail starts blur out > Sinus Sebaeus, Utopia Sinus may beother distinctive rather than to improve. visible. You and mayAurorae also see several Scandia

visible. You may also see several other distinctive

rather than improve. >



44

TOP: In 2005 large orographic white clouds were visible above prominent features on Mars. Here we see Olympus Mons as a clear white dot in the upper right quadrant with the clouds hovering over it. MIDDLE: The 2007 apparition of Mars began with the planet shrouded in a huge dust storm. This meant surface features were diffcult to resolve. The dust storm cleared as the planet reached opposition. BOTTOM: Beautiful wispy white clouds were on show during the 2012 opposition period, particularly over Olympus Mons and the Tharsis volcano region, which are visible across the centre of the planet.

44

TOP: In 2005 large orographic white clouds were visible above prominent features on Mars. Here we see Olympus Mons as a clear white dot in the upper right quadrant with the clouds hovering over it. MIDDLE: The 2007 apparition of Mars began with the planet shrouded in a huge dust storm. This meant surface features were diffcult to resolve. The dust storm cleared as the planet reached opposition. BOTTOM: Beautiful wispy white clouds were on show during the 2012 opposition period, particularly over Olympus Mons and the Tharsis volcano region, which are visible across the centre of the planet.

> Local dust storms are

another Martian feature to look out for in large scopes. Strong winds whip up the surface dust and push it into Mars’s atmosphere. These dust storm areas appear through the telescope as dust storms are > Local signifcantly brighter orangeanother Martian feature to yellow areas, which change look out for in large scopes. between and the next. Strong windsone whipday up the surface dust andmay push mask it into the normal albedo The dust Mars’s atmosphere. Theseand these storms can features in an area dust storm areas appear sometimes even go global, turning the planet into through the telescope as an almostbrighter featureless signifcantly orange-orange ball. One or two local dust events may be seen during this opposition, yellow areas, which change between onebigger day andglobal the next. but the dust storms are not likely; The may mask occur the normal albedo and September, theydust only really in August features in an area and these storms can when the planet is closer to the Sun and it receives sometimes even go global, turning the planet into extra heat necessary toOne power these anthe almost featureless orange ball. or two localevents. dust events may be seen during this opposition, but the bigger global dust storms are not likely; they only really occur August andthat September, Many people areinsurprised ice clouds or haze when the planet is closer to the Sun and it receives sometimes be seen on Mars – you can read more thecan extra heat necessary to power these events.

been seen to poke holes through the cloud about the Red Planet’s atmosphere on page 34. Chasing clouds layer. Imaging with a These features are seasonally related and again been seen Many people areimprove surprisedtheir that ice clouds or haze high frame rate camera flters help contrast. A blue flter to poke holes can sometimes be seen on Mars – you can read more (Wratten number #80A or #38A) is best to use here may be needed to make such through the cloud about the Red Planet’s atmosphere on page 34. visible, as they will be small as itfeatures darkens red areas compared more Imaging features with a These are the seasonally related and again to thelayer. this type of imaging allows you to see more on bluish cloud tends appear in the high frame rateand camera flters helpclouds. improve Hazy their contrast. A blue to flter to make such (Wratten number #80A #38A) is best to so usewill here be may planet than you can through visual observing early morning andorevening, and seenbeatneededthe features visible, as they will be Mars’, small right). as the it darkens the red areas compared to the more (see ‘Imaging western or eastern edges of the planet. Blue and this type of imaging allows you to see more on bluish clouds. Hazy cloud tends to appear in the A different type of cloud to the morning and hazy clouds also occur around the polar regions, so the planet than you can through visual observing early morning and evening, and so will be seen at evening hazes are the so-called orographic clouds, entire edge of planet. the planet and‘Imaging Mars’, right). theexamine western orthe eastern edges of the Blue with (see which form high regions and are sometimes without the blue flter to see if you can see signs A different type of cloud toover the morning and hazy clouds also occur around the polar regions, so evening hazes are the so-called orographic clouds, examine the entire edge of the planet with and seen centred on some of the larger Martian of these changing atmospheric features. which form over high regions and are sometimes without the blue flter to see if you can see signs volcanoes. During the 2005 opposition Olympus During the 2012 opposition, an extensive area seen centred on some of the larger Martian of these changing atmospheric features. Mons, volcano in the Solar System at of whitish morning cloud was evident in the volcanoes. During thethe 2005highest opposition Olympus During the 2012 opposition, an extensive area 27km, hadin a persistent orographic cloud around Tharsis of Mars. is the highest Mons, volcano the Solar System at of low-lying whitish morning cloudregion was evident in theThis region orographic around low-lying Tharsis region of Mars. This region it that was easily cloud seen as a small white patch. home to several huge volcanoes, andisthese 27km, have had a persistent

damian peach x 3, martin lewis x 4, dave holt, steve marsh x 3

damian peach x 3, martin lewis x 4, dave holt, steve marsh x 3

Chasing clouds

home to several huge volcanoes, and these have



it that was easily seen as a small white patch.


tHE four faCEs OF MARS

through a telescope, look for mars’s prominent features to work out which region you are looking at. these images are from the 2012 apparition with the north pole at the bottom


tHE four faCEs OF MARS

through a telescope, look for mars’s prominent features to work out which region you are looking at. these images are from the 2012 apparition with the north pole at the bottom 1 Syrtis Major

2 Mare Cimmerium

3 Eye of Mars

4 Mare Acidalium

(Central longitude: 320º)

(Central longitude: 198°)



This is the classic view of Mars, showing the prominent dark wedge shape of the Syrtis Major with the pipe-like Sinus Sabaeus off to the right.

After 11 days, the Mare Cimmerium is on view at the top. On the left, cloud over Olympus Mons shows up as a white patch. The Amazonis desert flls the centre.

Ten days later, Solis Lacus, known as the ‘Eye of Mars’, is seen at the top left and the dark fngers of Aurorae Sinus are seen upper left. The Mare Acidalium is lower left.

Another seven days on and the large shield-shaped Mare Acidalium sits above the north polar cap, while the Sinus Sabaeus reappears on the left-hand side.

iMAging mars

1 Syrtis Major

2 Mare Cimmerium

3 Eye of Mars

4 Mare Acidalium

(Central longitude: 320º)




This is the classic view of Mars, showing the prominent dark wedge shape of the Syrtis Major with the pipe-like Sinus Sabaeus off to the right.

After 11 days, the Mare Cimmerium is on view at the top. On the left, cloud over Olympus Mons shows up as a white patch. The Amazonis desert flls the centre.

Ten days later, Solis Lacus, known Another seven days on and the as the ‘Eye of Mars’, is seen at the large shield-shaped Mare best image is to sits above the north top The left and theway darkto fngers of planets Acidalium Aurorae Sinus seenthrough upper left. cap, while the Sinus Sabaeus record a are video yourpolar telescope The using Mare Acidalium is lower left.planetary reappears on the left-hand side. a high frame rate

camera and a Barlow lens, then Þ A 3x Barlow processing the resulting movie attached to a high frame to create a high-resolution still rate planetary imaging camera image. The fnal image uses only the best moments of seeing and The best way to image planets is to interesting images through any driven disregards the poor ones, and reveals record a video through your telescope telescope, although larger instruments much more surface detail than you using a high frame rate planetary will be able to show more detail. camera and a Barlow then couldlens, hope to see through the Þ AMars’s 3x Barlow processing the resulting movie high surface brightness allows eyepiece of the same scope. For the attached to a high frame to create a high-resolution still you to increase the image scale. For best images you can even try using an rate planetary imaging camera image. The fnal image uses only cameras with the popular pixel size of atmospheric the best moments of seeing anddispersion corrector, 5.6μm, try a Barlow lens that gives interesting images through any driven which reduces the prismatic effect of disregards the poor ones, and reveals telescope, although larger instruments much more surface detail than you effective focal ratios of f/25 to f/35, our atmosphere; an important will be able to show moreordetail. could hope to see through the even up to f/50 on exceptionally consideration given Mars’s lower Mars’s high surface brightness allows eyepiece of the same scope. For the steady nights. For cameras with smaller thisusing apparition. you to increase the image scale. For best images you altitude can even try an pixel sizes, drop these focal ratio Colour cameras give slightly less cameras with the popular pixel size of corrector, Þ With so much observing potential, sketching theatmospheric dispersion 5.6μm, try a Barlow lens that gives values in proportion to the pixel size. which reduces the prismatic detail thaneffect theirofmono counterparts, Red Planet is a uniquely rewarding challenge effective focal ratios of f/25 to f/35, our atmosphere;but an important The Red Planet completes one rotation they do dramatically speed up or even up to f/50 on exceptionally consideration given Mars’s lower in 24 hours and 37 minutes; so long and simplify both the steady imaging process nights. For cameras with smaller altitude this apparition. If you see signifcant detail on the planet, have a as ratio you complete your imaging within and theslightly follow-up needed. pixel sizes, drop these focal Colour cameras give less processing Þ With so much observing potential, sketching the fve minutes, you will avoid motion blur. go at making a sketch of what you see at the eyepiece. values in proportion to the pixel size. Mars is a relatively easy planet to detail than their mono counterparts, Red Planet is a uniquely rewarding challenge Theatmosphere Red Planet completes one Torotation fnd out how to image Mars with but they do dramatically up as the capture;speed as long is First spend some time looking without committing 24 hours and 37 minutes; so longCCD camera, turn to page 64. and simplify both the imaging process be in a mono steady you should able to get anything to paper. Thisonwill let youhave to tune into If you see signifcant detail the planet, a as you complete your imaging within andthe the follow-up processing needed. fve minutes, you will avoid motion blur. goscene at making a sketchdetails of what to youslowly see at the eyepiece. Mars is a relatively easy planet to allowing reveal themselves. To fnd out how to image Mars with capture; as long as the atmosphere is First spend some time looking without committing It’s a good idea to prepare some blanks in advance, a mono CCD camera, turn to page 64. steady you should be able to get anything to paper. This will let you to tune into the so draw 50mm circles on good-quality cartridge scene allowing details to slowly reveal themselves. you observe. It’s also worth using good It’spaper a goodbefore idea to prepare some blanks in advance, quality HB, B and perhaps 2B pencils. so draw 50mm circles on good-quality cartridge You could paper before observe.pencils It’s also to worth usingsome good of the even use you coloured depict quality HB, B and perhaps 2B pencils. You could different hues present if you’re feeling ambitious. even use coloured pencils to depict some of the Mars takes 24 ifhours 37ambitious. minutes to complete different hues present you’reand feeling a rotation, youand can37take your sketching Þ Stacking single frames from a video (left) creates a high-resolution image (right) Mars takes 24so hours minutes to time complete a rotation, so you canon take yourchanges time sketching > before the face show noticeably. The Þ Stacking single frames from a video (left) creates a high-resolution image (right) before the face on show changes noticeably. The >

iMAging mars



46 mars at opposition april

traCking bAckwARdS The planets orbiting the Sun farther than Earth generally track slowly eastwards through the constellations as the months pass. For several weeks either side of opposition, however, they appear to change direction and move westward, before later resuming their eastward track. The period where they seem to move in reverse called retrograde motion. It occurs because 46ismars at opposition april the faster-moving Earth overtakes a more distant planet, making it appear to move

East

backwards against the stars. You might see a similar effect on the motorway when overtaking a slower moving car – it appears to move backwards against the more distant scenery. During this apparition, Mars moves in a retrograde direction from 27 February to 18 May, from six weeks before opposition to six weeks after opposition, before recommencing its eastwards track towards Libra.

traCking bAckwARdS

The planets orbiting the Sun farther than Earth Porrima generally track slowly eastwards through the see a similar effect on the motorway constellations as the months pass. For several when overtaking a slower moving car – it 1 Jan weeks either side of opposition, however, they appears to move backwards against the appear to change direction and ζ move westward, more distant scenery. During this apparition, 1 May from 1 before later resuming their eastward track. Mars moves in a retrograde direction τ The period where they seem to move in reverse 278February to 18 May, from six weeks Apr is called retrograde motion. It occurs because before opposition to six weeks after (Opposition) the faster-moving Earth overtakes a more opposition, before recommencing its distant planet, making it appear to move eastwards track towards Libra.

East

East

West

Jun

Mars

θ

1 Apr

1 Feb

VIRGO

West

η

γ backwards against the stars. You might

VIRGO

East

Porrima

η Mars

γ1 Jul

Sun Earth

1 Jan

1 Mar ζ

τ

1 May

α

8 Apr (Opposition)

1 Jun

Spica

Mars’s path from the beginning of year through to July 2014

Þ As Earth overtakes Mars, the Red Planet appears to move backwards against the stars Mars

θ

1 Apr

Mars

the Martian day is about 40 minutes longer > fact that Sun than ours on Earth means that the planet appears to Earth rotate slowly backwards as the days pass. This Mars’s path from difference between a Martian day and an Earth day the 14 beginning of year This is a little less than arcseconds. Þ As Earth overtakes Mars, the Red Planet through to July 2014 also backwards means that youthe need due to Mars’s elliptical orbit, which causes appears to move against starsto wait about fve weeks for the same face to come into view again if you observe the Mars-to-Earth distance to be as little as 0.37 AU or as much as 0.67 AU. Mars at its highest each evening. A bit of planning is > fact that the Martian day is about 40 minutes longer needed, if you to want to see the whole of than ours on Earth means thattherefore, the planet appears 3 Mar 2012 rotate slowly backwards the days pass. theasMartian globeThis this spring. 13.9 arcseconds

AppARent diamEtEr 1 Feb

1 Jul

1 Mar

Although Mars oppositions occurα at Spica regular 26-month intervals, the apparent size of the planet at this time can vary widely, from just over 25 arcseconds to

Apr 2014 AppARent815.1diamEtEr arcseconds Although Mars oppositions occur at regular 26-month intervals, the apparent size of the planet at this time can vary widely, from just over 25 arcseconds to

22 May 2016 8 Apr 2014 15.1 arcseconds 18.4 arcseconds

difference between a Martian day and an Earth day also means that you need to wait about fve weeks for same face to come into view again if you observe Febthe 2027 Mars will be more than 15 Mars at its highest each evening. A bit of planning is arcseconds across from 13.8 arcseconds April and the middle of this period it will needed, therefore, if 5-23 you want to see theinwhole of the Martian globe this spring. be highest in the sky half an hour after midnight.

a little less than 14 arcseconds. This is due to Mars’s elliptical orbit, which causes the Mars-to-Earth distance to be as little19 as 0.37 AU or as much as 0.67 AU. 3 Mar 2012 13.9 arcseconds 19 Feb 2027 13.8 arcseconds

M

r cur y

Me

Venus

Ear t h e r cur y

Venus

M a rs Ear t h

M a rs

chart by pete lawrence, illustrations by steve marsh

chart by pete lawrence, illustrations by steve marsh

22 May 2016 18.4 arcseconds

Brief opportunity

By the end of May, however, it will have shrunk to Brief opportunity less than 12 arcseconds across and will be an hour

Mars will be more than 15 arcseconds across from its ofhighest position and in thepast middle this period it will when it gets dark at 10pm. 165-23 JanApril 2025 be highest in the sky half an hour midnight.planet with its albedo features Mars is aafter fascinating 14.5 arcseconds By the end of May, however, it will have to changes, so make the most and multitude ofshrunk seasonal less than 12 arcseconds across and will be an hour of April and May to see what you can make out on past its highest position when it gets dark at 10pm. 16 Jan 2025 the surface this kindred Mars is a fascinating planet with of its albedo features world. If you are able to, 14.5 arcseconds makechanges, some so record of the and multitude of seasonal make the mostplanet’s details this time of April and May to see what you make outsee on what changes occur between around. Youcan can then the surface of this kindred world. If you are able to, time it’ll be at its closest. S now and May 2016, the next make some record of the planet’s details this time 8 Dec 2022 around. You can then see what changes occur between 17.0 arcseconds now and May 2016, the next time it’ll be at its closest. S 8 Dec 2022 17.0 arcseconds

27 Jul 2018 24.2 arcseconds

27 Jul 2018 24.2 arcseconds

ABOUT THE WRITER

martin lewis is a keen astronomer. as a frequent reviewer for our First martin lewis is a keen astronomer. Light section, he has an in-depth as a frequent reviewer for our First knowledge of observing the planets Light section, he has an in-depth all sorts of equipment. knowledge of observing thewith planets ABOUT THE WRITER

13 Oct 2020 22.4 arcseconds

13 Oct 2020 22.4 arcseconds

with all sorts of equipment.



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The sky guide APRIL 51

plus Stephen Tonkin’s

BINOCULAR TOUR Turn to page 62 for six of this month’s best binocular sights The sky guide APRIL 51

plus Stephen Tonkin’s

BINOCULAR TOUR Turn to page 62 for six of this month’s best binocular sights

The

April April Sky Guide The

pete lawrence

pete lawrence

Sky Guide

Mars reaches opposition this month. At this time, the planet will appear at its Mars reachesbrightest oppositionand this largest month. Atfor the current period this time, the planet will appear at its of observation. Located in the constellation of brightest and largest for the current period Written by Pete Lawrence Virgo, a telescope will reveal of observation. Located in the constellation of tantalising details as well as writing The Sky Guide, pete Written by Pete Lawrence on thiswillenigmatic world.details reveal tantalising can be seen on The Sky at Night on Virgo, BBc a telescope as well as writing The Sky Guide, pete Four. On page 64, he offers adviceon on this enigmatic can be seen on The Sky at Night on BBc how to avoid motion blur when imaging Four. On page 64, he offers advice on with ablur mono high frame rate camera. how toMars avoid motion when imaging Mars with a mono high frame rate camera.

world.



52

Highlights Your guide to the night sky this month this icon indicates a good photo opportunity

1

Tuesday the Moon’s crescent phase and libration make this a good time to view crater Humboldt, pictured. See page 63.

52

Highlights

the best periods to take this month’s Deep-sky tour are from tonight until the 7th and from the 24th until the 30th. See page 60.

Your guide to the night sky this month this icon indicates a good photo opportunity

1

Tuesday the Moon’s crescent phase and libration make this a good time to view crater Humboldt, pictured. See page 63.

the best periods to take this month’s Deep-sky tour are from tonight until the 7th and from the 24th until the 30th. See page 60.

8

6

sunday the waxing crescent Moon (45% lit) will lie just 6º south of Jupiter this evening. at mag. –2.0 the planet will be obvious sunday above the lunar disc. the

6

waxing crescent Moon (45% lit) will lie just 6º south of Jupiter this evening. at mag. –2.0 the planet will be obvious above the lunar disc.

8

Tuesday Mars comes to opposition in Virgo. the planet has an apparent diameter of 15.1 arcseconds and the north polar cap should be fairly obvious through a telescope. around Tuesday midnight, the dark V-shaped Mars comes to feature known opposition in as the Syrtis Major Virgo. thecoming planet has will be into view.

10

10

Moon (81% lit) is mag. +1.3 regulus an apparent diameter of 15.1 (alpha (a) leonis). regulus should arcseconds and the north polar be easy to spot, but see if you can cap should be fairly obvious  the fainter stars of the also pick out through a telescope. around Thursday full Sickle asterism, which extend above midnight, the dark V-shaped the almost in the shape of a feature known as the Syrtis Major Moon regulus (96% lit) backwards question mark. will be coming into view.

17

is just 2.5º from Saturn this morning, low in the southwest. Both  objects will be Thursday thefrom almost full visible around 22:30 BSt Moon lit) april, with the (21:30 Ut)(96% on 16 is just 2.5º from Moon slowly but surely closing Saturn this morning, low in the on the planet as dawn breaks. southwest. Both objects will be

17 the dark Martian wednesday feature known dark as the Syrtis Majorthe is centrally Martian located on thefeature planet’s disc around known midnight. a small telescope can as the Syrtis Major is centrally located on the planet’s disc around show this V-shaped object well midnight. telescope can with but, asaissmall always the case show this V-shaped object well Mars, give your eye time to but, as is always the case with become accustomed Mars, give your eye time to to the view.

pete lawrence x 8

pete lawrence x 8

23 23

visible from around 22:30 BSt (21:30 Ut) on 16 april, with the Moon slowly but surely closing on the wednesday  planet as dawn breaks.

become accustomed to the view.



14

Thursday monday the bright star tonight’s 5.5º to the north of full Moon the waxing gibbous lies conveniently Moon (81% lit) is mag. +1.3 regulus between Mars and mag. +1.0 (alpha (a) leonis). regulus should Spica (alpha (a) Virginis). the be easy to spot, but see if you can star should stand out despite the also pick out the fainter stars of the Moon’s glare. Orange-hued Thursday monday Sickle asterism, which extend above Mars, shining at mag. –1.5, will the bright star tonight’s regulus in the shape of a be even more obvious above the 5.5º to the north of full Moon the backwards waxing gibbous lies conveniently question mark. Moon’s disc.

14

between Mars and mag. +1.0 Spica (alpha (a) Virginis). the star should stand out despite the Moon’s glare. Orange-hued Mars, shining at mag. –1.5, will be even more obvious above the Moon’s disc.

19

saTurday the eta aquariid meteor shower becomes active from now until 28 May. the peak zenithal hourly rate of this saTurday the eta aquariid shower is typically 45 meteors meteor shower per hour. peak activity occurs becomes active early next month, on 6 May. from now until 28 May. the peak

19

zenithal hourly rate of this shower is typically 45 meteors per hour. peak activity occurs early next month, on 6 May.

26 27 26 27

saTurday sunday  a lovely the sight whirlpool saTurday awaits earlysunday  Galaxy, M51, a lovely risers: the waning crescent Moon the is virtually overhead at midnight. sight whirlpool (11% lit) lies close to brilliant Venus this is a great opportunity to get awaits early Galaxy, M51, in the Moon dawn twilight. look for theat midnight. better acquainted with this risers: the waning crescent is virtually overhead (11% lit) lies close topair brilliant Venus 05:00 this isBSt a great opportunity towonderful get around (04:00 object. in the dawn twilight.Ut); lookthe for the better acquainted with this Moon will appear to the pair around 05:00 BSt (04:00 wonderful object. left of Venus from the UK. Ut); the Moon will appear to the left of Venus from the UK.


what the team will be observing in april Pete Lawrence “This month’s highlight has to be the planet Mars and I intend to catch it at every opportunity. I can’t wait The skyoutside guideand APRIL 53 some images of to get take this amazing planet.”

2

wednesday  the familiar plough asterism is virtually overhead around midnight. as the Moon is not around, this is a great time to investigate some of the deep-sky objects on offer in this area, such as the Owl nebula, shown right, and the lovely galaxy pair M81 and M82.

Chris Bramley “There are two sights I want to catch this month. The frst is the Syrtis what the team will be Major on Mars; I'll also have a sunlounger observing in april and sleeping bag at the ready on the 22nd, the“This April Lyridhighlight meteorhas shower peaks.” Pete when Lawrence month’s

2

to be the planet Mars and I intend to catch it at every Paul opportunity. I can’t money “I’ll wait be tracking and to get outside and take some images of photographing the motion of Ceres this amazing planet.”

wednesday  the familiar plough asterism Thursday is virtually overhead waxing around midnight. as the the Moon is crescent not around, this is a great time to Moon investigate some of the deep-sky (18% lit) lies close to the objectsHyades on offer open in this area, cluster in taurus this such as the Owl nebula, shown evening. look out for them around right, and the lovely galaxy pair 21:30 M81 and M82.BSt (20:30 Ut). the Moon

3

and Vesta as they come to opposition this Chris Bramley “There arein two sights not I want month Virgo, far from Mars.”

to catch this month. The frst is the Syrtis Major on Mars; I'll also have a sunlounger and sleeping bag at the ready on the 22nd, when the April Lyrid meteor shower peaks.”

should also be showing earthshine, which causes its dark portion to become dimly visible.

3

Thursday the waxing crescent Moon (18% lit) lies close to the Hyades open cluster in taurus this evening. look out for them around 21:30 BSt (20:30 Ut). the Moon should also be showing earthshine, which causes its dark portion to become dimly visible.

need to know

Paul money “I’ll be tracking and photographing the motion of Ceres and Vesta as they come to opposition The terms and symbolsthisused month in Virgo, not far from Mars.”

15

 Tuesday Dwarf planet ceres and minor planet Vesta both come to opposition in Virgo. See page 54.

15

in The Sky Guide

univeRSaL Time (uT) and BRiTiSH SummeR Time (BST) Universal Time (UT) is the standard time used by astronomers around the world. British Summer Time (BST) is one hour ahead of UT.

(RiGHT aSCenSion) and deC. (deCLinaTion) need toRa know These coordinates are the night sky’s equivalent of longitude and

symbols used in The Sky Guide You may be able to seeThe the terms start of and latitude, describing where an object lies on the celestial ‘globe’.  Tuesday the penumbral a total lunar Time (uT) and BRiTiSH SummeR Time (BST) Dwarf phase planet ofuniveRSaL eclipse asceres the Moon sets at 06:00 and Universal Time (UT) is the standard time used by astronomers around HoW To TeLL WHaT equiPmenT you’LL need minor planet the world. Time (BST) is one hour ahead of UT. BSt (05:00 Ut). See page 55. British Summer

21

Vesta both come to opposition in Virgo. See page 54.

22

Ra (RiGHT aSCenSion)naKed and deC. (deCLinaTion) eye These coordinates are the night sky’s20 equivalent offor longitude and to become dark-adapted Allow minutes your eyes Tuesday

mondayYou may be able to see the start of latitude, describing where an object lies on the celestial ‘globe’. the enigmatically tonight is the penumbral phase of a total lunar BinoCuLaRS eclipse as the Moon sets at 06:00 named realm the peak HoW To TeLL WHaT equiPmenT you’LL need 10x50 recommended of GalaxiesBSt is (05:00 Ut). See page 55. of the annual due south at 23:30 BSt (22:30 lyrid meteor shower, which is active naKed eye your eyes tooPPoRTuniTy become dark-adapted Ut). locatedmonday within the asterism from 16-26 april. the normal Allow peak 20 minutes for PHoTo Tuesday the enigmatically tonight is known as the Bowl of Virgo, this zenithal hourly rate for this shower Use a CCD, planetary camera or standard DSLR named realmin faint the peak area of the sky is rich is 10 meteors per hour, but BinoCuLaRS 10x50 recommended of Galaxies is of the annual galaxies, many of which canlyrid be meteorinfrequent outbursts have been due south at 23:30 BSt (22:30 shower, which is active SmaLL/medium SCoPe withwithin a small telescope. from 16-26recorded. See page Ut).seen located the asterism april. the normal peak 55. PHoTo oPPoRTuniTy Reflector/SCT under 6 inches, refractor under 4 inches

21

known as the Bowl of Virgo, this area of the sky is rich in faint galaxies, many of which can be seen with a small telescope.

22

zenithal hourly rate for this shower Use a CCD, planetary camera or standard DSLR is 10 meteors per hour, but infrequent outbursts have been LaRGe SCoPe SmaLL/medium SCoPe recorded. See page 55. wednesday Reflector/SCT under Reflector/SCT 6 inches, refractorover under64inches, inches

30 30

refractor over 4 inches Keep an LaRGe SCoPe eye out Reflector/SCT over 6 inches, refractor over 4 inches wednesdayfor a slender an and rather Keep beautiful waning eye out crescent just after sunset. forMoon a slender Once the Sun has dipped below and rather beautiful waning If you’re new to astronomy, you’ll find two crescent Moon just after sunset. the horizon, keep an eye out for Once the Sun has dipped below essential reads on our website. Visit http:// mag. –1.7 Mercury very low If you’re new to astronomy, you’ll find two the horizon, keep an eye out for bit.ly/10_lessons for our 10-step guide to down in the west-northwest. essential reads on our website. Visit http:// mag. –1.7 Mercury very low getting started bit.ly/10_lessons for our 10-step guide to and http://bit.ly/First_tel down in the west-northwest. for advice on choosing your first scope. getting started and http://bit.ly/First_tel

Getting started in astronomy Getting started in astronomy

for advice on choosing your first scope.



54

don’T miss… 54

3 top sights

Ceres and Vesta at opposition

WHen: all month

don’T miss…

mag. +5.9, increases to mag. +5.8 around opposition before falling back to mag. +5.9 again. This places Vesta just within the bounds of naked-eye visibility under dark skies. Like Ceres, Vesta is also in Virgo b Auva and appears to be travelling WHen: all month along the same part of the sky. 1 May 78 1 May At the start of the month, it mag. +5.9, increases to mag. 21 Apr Ceres can be found just to the west of 21 Apr +5.8 around opposition before 84 11 Apr falling back to mag. +5.9 Tau again.Virginis. it then heads on a This places Vesta just within similar path to Ceres towards 11 Apr Vesta 1 Apr the bounds of naked-eye 78 Virginis, which it lies close VIRGO visibility under dark skies. Like to by the end of April. 1 Apr Ceres, Vesta is also in Virgo CU b c Auva t and appears to be travellingif you have clear skies and 92 DSLR, these close encounters along the same part of thea sky. Heze 1 May 78 1 May At the start of the month,will it give you a great opportunity 21 Apr Ceres can be found just to the west of 21 Apr to record the journeys. A 100mm 84 Tau Virginis. it then heads on a 11 Apr lens will produce an image similar path to Ceres towards 11 Apr Vesta 15 Apr Mars 1 Apr º frame 12 across. Centre on 78 Virginis, which it lies close to by the end of April. 84 Virginis and take as many 1 Apr CU c t shots as you can over the eif you have clear skies and 92 a DSLR, these close encounters Heze course of the month. Load them will give you a great opportunity 1 Apr into a layer-based image editor to record the journeys. A 100mm such as Photoshop or GimP as lens will produce an image Ceres and vesta both pass 84 virginis during april, the star acting as a reference15point to their progress Apr Mars º frame 12 across. Centre separate on layers, then align 84 Virginisasand common stars between frames. of Ceres and classifed a take as many back in 2006, at the same time NASA’S DAwN miSSioN is shots as you can over the Finally, set the blend mode of Despite being the international Astronomical e minor planet. course approaching its second phase, of the month. Load them all images, except the lowest smaller than Ceres, Vesta is defnitions of with the spacecraft getting ever Union refned the 1 Apr into a layer-based image editor one, brighter; in fact theasbrightest what makes a planet ‘a planet’. closer to dwarf planet Ceres. such Photoshopof or GimP as to ‘Lighten’. This should Ceres and vesta both pass 84 virginis during april, the star acting as a reference point to their progress separate layers, then align reveal the passage of Ceres and all the minor planets. During Dawn is due to reach Ceres Both Ceres and minor planet common stars between frames. of Ceres and classifed as a back in 2006, at the same time NASA’S DAwN miSSioN is Vesta across the night sky. April its magnitude starts at in spring 2015, so we should Vesta – Dawn’s previous stop Finally, set the blend mode of the international Astronomical minor planet. Despite being approaching its second phase, know lot moreofabout thisthan Ceres, Vesta is – are in the same partever of theUnion sky refned all images, except the lowest smaller theadefnitions with the spacecraft getting amazing world next year. and enter opposition on the 15th. brighter; in fact the brightest of one, to ‘Lighten’. This should what makes a planet ‘a planet’. closer to dwarf planet Ceres. reveal the passage of Ceres and all the at minor planets. During to reachstarts Ceres the month Both Ceres Ceres and wasminor onceplanet the king Dawn of is due Ceres Vesta across the night sky. its magnitude starts at we should Vesta Dawn’s planets. previous stop mag.so+7.1, making itApril an easy the–minor with a in spring 2015, – are in the same part of the sky know a lot more about this diameter of just under 1,000km, binocular target. it brightens and enter opposition on the 15th. amazing world next year. by athe tiny amount to mag. +7.0 it’s a was body massive for Ceres starts month at Ceres once the kingenough of on 15 April, to mould mag.a+7.1,around making itopposition an easy thegravity minor planets. withitsa shape into binocular before target. itdropping brightens back to mag. diameter just under 1,000km, sphere.ofUltimately this led to by a tiny amount to mag. it’sCeres a bodybeing massivepromoted enough for from +7.1 again by+7.0 the end of the gravity to mould its shape into a around opposition on 15 April, month. Throughout April it minor planet to dwarf planet before dropping back to mag. sphere. Ultimately this led to from just north of mag. +7.1 againmoves by the end of the Ceres being promoted from +4.2 Tau (t) Virginis to a minor planet to dwarf planet need To know month. Throughout April it moves from just north of mag. mag. +5.4 position between an object’s brightness is+4.2 Tau (t) Virginis to a need To know 84 Virginis and ffth-magnitude given by its magnitude. the position between mag. +5.4 an object’s brightnessthe is brighter variable star 78 Virginis. lower the number, 84 Virginis and ffth-magnitude given by its magnitude. the the object: with the naked eye is Vesta, a body with variable star Nearby 78 Virginis. lower the number, the brighter can see the you object: with thedown naked to eyemag. +6.0. Nearby ais mean Vesta, adiameter body with just half that at mag. +5.9 for much of the month, vesta is near naked-eye visibility

3 top sightsVIRGO

pete lawrence x 4

pete lawrence x 4

Ceres and Vesta at opposition

!

!

you can see down to mag. +6.0.

a mean diameter just half that



at mag. +5.9 for much of the month, vesta is near naked-eye visibility


April Lyrid meteor shower WHen: 16-26 april; peak occurs on the 22nd

HERCULES


Total lunar eclipse

e

15 Apr

April Lyrids Radiant

Vega

April Lyrid meteor shower

20 Apr 22 Apr

Deneb

Summer

Triangle

25 Apr

CYGNUS

LYRA

HERCULES

VULPECULA Keyston

e

15 Apr

April Lyrids Radiant

Vega

SAGITTA 20 Apr 22 Apr

gle

AQUILA

25 Apr

Trian Summer

CYGNUS

ta Al

DELPHINUS

ir

LYRA

VULPECULA

The shower radiant lies between the Summer Triangle and Keystone asterisms SAGITTA lyrids occur roughly every 60 years, with 700 meteors per hour AQUILA recorded in 1803. sadly, the

DELPHINUS

last one was in 1982, so we’re not expecting to see anything out of the ordinary this time.

ta ir

Thatcher. its meteors appear from the evening sky on the to emanate from a location 22nd; it rises at around 03:15 slightly off to the west of mag. BsT (02:15 UT) on the 23rd, 0.0 Vega (Alpha (a) lyrae), when it will show a waning with an average trail crescent (41% lit) phase. brightness of mag. +2.0. The April lyrids typically WHen: 05:30 uT) from on 15theapril Outbursts April show a peakFrom of around 10 BST (04:30

Keyston

Al

meteors per hour. This is the The April lyrids are one zenithal hourly rate – the of the regular annual meteor value that indicates the showers and a welcome break from the relatively sparse period number of meteors you’d see if the shower radiant, where of meteor activity that occurs the meteors appear to emanate at the start of the year. The from, were directly overhead. shower is active from 16-26 The zenithal hourly rate April, peaking on the 22nd. fgure is only a guide, however, The Moon is going to WHen: 16-26 april; peak occurs on the 22nd as it assumes perfect skies and interfere at the start of this period, being fractionally past the fact that you can see the meteors per hour. This is the The April lyrids are one entire sky in one go – which full on the night of the 16th, zenithal hourly rate – the of the regular annual meteor you can’t! rising at 21:50 BsT (20:50 UT). value thatunfortunately indicates the showers and a welcome break however, oversparse the next days ofConsequently, meteors you’d seethe visually from the relatively periodfewnumber if the shower radiant,rate where of the meteor activity that occurs observed will be lower. Moon’s decrease in phase, the meteors appear to emanate at the start of the year. The The April lyrids are a result coupled with it slipping from, were directly overhead. shower is active from 16-26 of earth passing the farther to the south and east Deneb The zenithal hourly rate through April, peaking on the 22nd. dust stream spread along the in the sky, will aid a guide, however, The Moon is going to meteorfgure is only as it assumes perfect skies and interfere at theThe startMoon of this is absent orbit of comet C/1861 G1 visibility. the fact that you can see the period, being fractionally past Thatcher. its meteors appear from the evening sky on the entire sky in one go – which full on the night of the 16th, to emanate from a location 22nd; it rises at around 03:15 rising at 21:50 BsT (20:50 UT). unfortunately you can’t! slightly off to the west of mag. BsT (02:15 UT) Consequently, the visually however, over the nexton fewthe days23rd, 0.0 Vega it decrease will show a waning observed rate will be(Alpha lower. (a) lyrae), thewhen Moon’s in phase, lyrids a resulttrail coupled with(41% it slipping with an are average crescent lit) phase. The April of earth passing through farther to the south and east brightness ofthe mag. +2.0. The April lyrids typically dust stream spread along the in the sky, will aid meteor Outbursts from the April show a peak of around 10 orbit of comet C/1861 G1 visibility. The Moon is absent

The shower radiant lies between the Summer Triangle and Keystone asterisms

lyrids occur roughly every 60 years, with 700 meteors per hour recorded in 1803. sadly, the

last one was in 1982, so we’re not expecting to see anything out of the ordinary this time.

hint of shading from the A ToTAL LUNAR eclipse penumbral part of the eclipse takes place on 15 April. can’t be predicted with Unfortunately the main part certainty, but it’s always worth occurs after the moon has set going out to have a look. for observers in the UK, but WHen: From 05:30 BST (04:30 uT) on 15 april hint of shading from the A ToTAL LUNAR eclipse Locate the full moon at you may be able to catch the penumbral takes place on 15 beginning April. 05:30 BST (04:30 UT) and you of the event. part of the eclipse can’t be predicted with Unfortunately the main part The partbut of it’s thealways should certainty, worth see bright mars off to occurs after the moon hasmain, set dark the right and fainter, mag. shadow, known as the umbra, going out to have a look. for observers in the UK, but Locate the full you may be able to catch the begins to cross the lunar discmoon at+1.0 Spica (Alpha (a) 05:30 BST (04:30 you beginning of the at event. Virginis), just 1º from the 06:58 BST (05:58 UT), by UT) and should see bright mars off to The main, dark part of the moon’s centre, off to the lower which point the moon will be the right and fainter, mag. shadow, known as the umbra, no longer visible from the UK. +1.0 Spica (Alpha (a) left. As the moon gets closer begins to cross the lunar disc to the horizon it will be nicely But webyshouldVirginis), be able just to see 1º from the at 06:58 BST (05:58 UT), moon’s lower in the Belt of Venus which point the moon will be outer the fainter, partcentre, of off to thelocated left. As the moon gets closer no longer visible from the UK. – the projection of the closer Earth’s shadow, known as the to the horizon it will be nicely But we should be able to see part of Earth’s shadow in the penumbra, begin to encroach located in the Belt of Venus the fainter, outer part of atmosphere. on theaslunar – the projection of the closer Earth’s shadow, known the disc. The penumbra frst starts part of Earth’s shadow in the penumbra, begin to encroach need To know atmosphere. on the lunar disc.to cross the edge of the moon the planets of the Solar The penumbra frst starts at 05:53 BST (04:53need UT), To when know System occupy similar orbital to cross the edge of the moon The orionids peak on 21 planetsthe of the Solar planes; it is this ‘co-planar’ nature the moon is still 2ºthe above at 05:53 System occupy similar orbital october, but you’ll haveBST to (04:53 UT), when that allows us to see conjunctions The orionids peak on 21 west-southwest the moon is still UK’s 2º above the planes; ithorizon. is this ‘co-planar’ nature with october, butcontend you’ll have to a bright moon from our perspective on earth. us to see conjunctions west-southwest horizon.we getthat whether toallows see any mag. +1.0 Spica sits below and leftcontend of the with moon as the eclipse UK’s begins a bright moon

Total lunar eclipse

!

mag. +1.0 Spica sits below and left of the moon as the eclipse begins

whether we get to see any

!

from our perspective on earth.



56

`

BOÖTES

The planets

Arcturus

a Vindemiatrix

¡

Pick of The monTh

`

56

MARs

BeST Time in aPRiL: 8 April, 01:22 BST (00:22 UT) aLTiTude: 31º LoCaTion: Virgo diReCTion: South ReCommended equiPmenT: Pick of Thetelescope monTh 6-inch or larger FeaTuReS oF inTeReST: MARs Polar caps, dark markings, BeST Time in aPRiL: clouds and dust storms.

The planets

g c BOÖTES Arcturus

LEO30th

Mars

a ¡

1st

`

a VIRGO

d Porrima

`

Heze

Vindemiatrix

Zavijava

b

VIRGO

8 April, 01:22 BST (00:22 UT) mARS REAChES oPPoSiTioN on aLTiTude: 31º 8 April and is visible all night long. on LoCaTion: Virgo diReCTion: South this date the planet will be in the opposite ReCommended part of the skyequiPmenT: to the Sun and appear 6-inch larger telescope at itsorbrightest for the current FeaTuReS oFobservation inTeReST: period of Polar caps, dark markings, at mag. –1.5. clouds and dust storms.

Zavijava

Spica

b g

d

CORVUS

Porrima

c

30th

Heze throughout april; it won’t be hard to find, blazing away at a brilliant mag. –1.5 mars stays in virgo Mars

the martian equivalent of the Greenwich ‘V’ points north. we’ve indicated a 1st meridian on the martian globe. Another couple of times to look out for (this time bright) feature that should be the Syrtis in this Spica a major fairly easy to spot with a small telescope is month’s highlights CORVUS the planet’s north polar cap. calendar on pages mars continues to get closer to Earth 52-53. it is just one mars stays in virgo throughout april; it won’t be hard to find, blazing away at a brilliant mag. –1.5 and so appear larger through a telescope of several features about a week following opposition. on appear dark martian equivalentfor of the Greenwich ‘V’ points north. we’ve indicated a that the meridian on the martian theglobe. 15th Another the planet achieves an apparent couple of times to look out for against mars’s (thisdeserts. time bright) feature that should be arcseconds. Though this the Syrtis major in this lighter diameter of 15.2 fairly easy to spot with a small telescope is month’s highlights is not much more than that shown on the Roughly four the planet’s north polar cap. calendar on pages 8th, where mars is concerned every little hours mars continues to get closer to Earth 52-53. it is just oneand a half bit is most welcome. after the Syrtis major and so appear larger through a telescope of several features about a week onthe month, mars is mag. that appear dark Atopposition. the end of is on thefor centreline of following 15thathe planet achieves against mars’s –1.2, an hasapparent an apparent diameter of 14.6 the planet’sthe disc, diameter of 15.2 arcseconds. Though this lighter deserts. arcseconds and sits 1.5º from mag. +3.4 smaller two-pronged feature is not much more than that shown on the Roughly four Porrima (Gamma (g) Virginis). For more comes into view; one of the 8th, where mars is concerned every little mars’s north polar and a half hours prongs is known Sinus bitthe is most welcome. tips on observing mars at opposition, turn the Syrtis major as cap should be after At the end of the month, mars is mag. feature on page 41. is on the centreline of to our in-depth an easy spot meridiani. This feature marks

At the start of

mARS REAChES oPPoSiTioN on the month mars 8 April and is visible all night long. on appears to be 14.7 this date the planet will be in the opposite arcseconds part of the sky toacross the Sun and appear at its brightest for the current when viewed period of observation through a at mag. –1.5. telescope. At this At the start of small scope thescale, montha mars should be capable of appears to be 14.7 arcseconds across revealing the main when viewed on the planet, markings through a such as the V-shaped Syrtis telescope. At this major. The ‘V’ description only scale, a small scope really should be works capable in of an inverted revealing the main telescopic view as the tip of the –1.2, has an apparent diameter of 14.6 markings on the planet, the planet’s disc, a arcseconds and sits 1.5º from mag. +3.4 such as the V-shaped Syrtis smaller two-pronged feature Porrima (Gamma (g) Virginis). For more major. The ‘V’ description only comes into view; one of the mars’s north polar tips on observing mars at opposition, turn really works in an inverted prongs is known as the Sinus cap should be to our in-depth feature on page 41. an easy spot telescopic view as the tip of the meridiani. This feature marks The phase, tilt and relative sizes of the planets in April. Each planet is shown with south at the top, to show what it looks like through a telescope

pete lawrence x 2 pete lawrence x 2

LEO

How the planets will appear this month

venuS maRS JuPiTeR How the planets will appear this month 15 apr 15 apr 15 apr

SaTuRn 15 apr

The phase, tilt and relative sizes of the planets in April. Each planet is shown with south at the top, to show what it looks like through a telescope

meRCuRy 1 apr

venuS 15 apr

maRS 15 apr

JuPiTeR 15 apr

SaTuRn 15 apr

meRCuRy 1 aprmeRCuRy

uRanuS 15 apr

nePTune 15 apr

noT viSiBLe

noT viSiBLe

uRanuS 15 apr

nePTune 15 apr

noT viSiBLe

noT viSiBLe

15 apr meRCuRy 15 apr

meRCuRy 30 apr

meRCuRy 30 apr

0” 0”



10”

20” 30” 40” aRCSeCondS

10” 50”

1’

20” 30” 40” aRCSeCondS

50”

1’

MeRCURy

up in the southwest as the sky darkens. At the start of BeST Time in aPRiL: April the planet shows a 30 April, 21:00 BST 38-arcsecond disc when (20:00 UT) viewed through a telescope, aLTiTude: 1º (low) plenty big enough to show LoCaTion: Aries some great detail even with diReCTion: West-northwest small instruments. on the mercury spends most of the 6th, the waxing crescent month poorly placed in the Using a small scope you’ll be able to spot Saturn’s biggest moons. morning sky, with both planet moon (45% lit) lies 6º below their positions change dramatically during the month, as shown on and Sun rising at approximately the planet. By the end of the the diagram. the line by each date on the left represents midnight. month, the distance between the same time. Superior up in the southwest as the MeRCURy us and Jupiter will have conjunction occurs on the sky 26th DATE WEST EAST darkens. At the start of BeST Time in aPRiL: increased, in the the21:00 prospects April the planet shows resulting a 30and April, BST for spotting 1 slightly mercury are planet 38-arcsecond disc appearing when (20:00 UT) in the evening sky 2 n’S mo onS viewed through a telescope, smaller at 35 arcseconds S a T u R aLTiTude: 1º (low) much better. See if you can catch enough to show LoCaTion: Aries and slightly fainter at a glimpse of the mag. –1.7plenty bigacross, 3 some great detail even with diReCTion: West-northwest mag. –1.9. The planet remains planet very low on the westsmall instruments. on the mercury spends most of the 4 in Gemini all month. northwest horizon shortly after 6th, the waxing crescent month poorly placed in the Using a small scope you’ll be able to spot Saturn’s biggest moons. moon (45% lit) lies 6º below sunsetsky, at the the month. morning withend bothof planet 5

S aT u R n ’S m o o n S

April

April

and Sun rising at approximately the planet. By the end of the month, the distance between the same time. Superior VeNUs sATURN conjunction occurs on the 26th us and Jupiter will have BeST Time in aPRiL: Time in aPRiL: increased,BeST resulting in the and the prospects for spotting 25 and 26evening April,sky 05:20 BST appearing 30 April, 02:00 BST slightly mercury in the are planet 35 arcseconds much better. See (04:20 UT)if you can catch smaller at(01:00 UT) across, and slightly fainter a glimpse of the5º mag. –1.7 aLTiTude: (low) aLTiTude: 21ºat mag. –1.9. The planet remains planet very low on the westLoCaTion: Aquarius LoCaTion: Libra northwest horizon shortly after in Gemini all month. diReCTion: East diReCTion: South sunset at the end of the month.

their positions change dramatically during the month, as shown on the diagram. the line by each date on the left represents midnight.

6

DATE

2

8

3

9

4

10

5

NOT VISIBLE THIS MONTH URANUs, NepTUNe

feld of view calculator on our website at: http://www.skyatnightmagazine.com/astronomy-tools http://www.skyatnightmagazine.com/astronomy-tools

12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 1 3

1

See what the planets look like through your telescope with the 3 feld of calculator on our website See what the planets lookview like through your telescope with the at: Tethys

EAST

11

Venus is a morning object that Sitting in the constellation 6 VeNUs shines brighter than mag. sATURN –4.0 of Libra, Saturn doesn’t get BeST in aPRiL: BeST Timevery in aPRiL: 7 allTime month. Despite this, the high above the UK’s 25 and 26 April, 05:20 BST 30 April, 02:00 BST planet’s aspect as seen from southern horizon, even 8when (04:20 UT) (01:00 UT) the UK5ºis (low) worsening; it’s quite aLTiTude: aLTiTude:due 21º south. Don’t let that9deter LoCaTion: Aquarius LoCaTion: Libra low in the dawn twilight prior you though. if you have 10a diReCTion: East diReCTion: South to sunrise. A telescope will telescope, it’s defnitely worth 11 Venus is a morning object that Sitting in the constellation now show its disc to have a trying to get a view of this shines brighter than mag. –4.0 of Libra, Saturn doesn’t get 12 phase.this, At the the startvery high beautiful planet. allgibbous month. Despite above the UK’s of April, tosouthern be At theeven start of April, 13 Saturn planet’s aspectVenus as seenappears from horizon, when the22 UK is worsening;across it’s quite that deter arcseconds with due a south.isDon’t mag.let+0.6 and its disc 14 lowphase in the of dawn twilight prior end, you though. if you have a 18 arcseconds 54%. By month appears to be 15 to sunrise. A telescope will telescope, it’s defnitely worth this will have changed to across. it rises at 22:30 BST now show its disc to have a trying to get a view of this 16 17 arcseconds and a phase of (21:30 UT) on the 1st and gibbous phase. At the start beautiful planet. 17 Look appears out fortoattractive manages toSaturn reach its highest of 66%. April, Venus be At the start of April, 22conjunctions arcseconds across with a Venus is mag. +0.6 and in its disc between point the sky, 21º up18 and phase of 54%. By month end, appears to be 18 arcseconds and the waning crescent moon due south, in darkness.19The this will have changed to across. it rises at 22:30 BST the east-southeast sky UT)almost fulland moon lies just 20 17 in arcseconds and a phase ofdawn(21:30 on the 1st º on the 25th and 26th. 2 from Saturn in the early 66%. Look out for attractive manages to reach its highest 21 conjunctions between Venus point in the sky, 21 hours ofº up 17 and April. Look out 22 and the waning crescent moon due south,for in darkness. the pair The low in the JUpITeR in the east-southeast dawn sky almost full moon lies just 23 southwest at around 05:30 BeST Time in aPRiL: on the 25th and 26th. 2º from Saturn in the early BST (04:30 end 1 April, 21:30 BST hours of 17 April. LookUT). out At the 24 oflow theinmonth, Saturn is25 (20:30 UT) for the pair the JUpITeR southwestvisible at around BeST Time in aPRiL: all05:30 night long and aLTiTude: 52º 26 BST (04:30this UT).isAtthe the best end time to try 1 April, 21:30 BST LoCaTion: Gemini 27 of the month, Saturn is (20:30 UT) get a view of it. diReCTion: Southwest visible all and night long and aLTiTude: 52º 28 Jupiter isGemini best seen at the start this is the best time to try LoCaTion: 29 of April,Southwest when its impressive NOTof VISIBLE THIS MONTH and get a view it. diReCTion: Jupiter is best seen at the start º mag. –1.2 dot can be seen 52 URANUs, NepTUNe 30 of April, when its impressive mag. –1.2 dot can be seen 52º

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Deep-sky tour There’s much more to see in the skies around Libra than the ringed wonder of Saturn ✓ Tick the box when you’ve seen each one 60 If you have a large scope, look for the ‘strings’ of stars streaming from M5’s core

Deep-sky tour There’s much more to see in the skies around Libra than the ✓ 

Tick the box when you’ve seen each one If you have a large scope, look for the ‘strings’ of stars streaming from M5’s core

3

Continue south from Palomar 5 and you’ll reach the constellation of Libra and our next target – mag. +2.6 Zubeneschamali (Beta (β) Librae). This star is distinct because of reports that it appears to have a green tint. If true, this makes it the only greenish star in the sky visible to the naked eye. A star with peak output in the green part of the ringed wonder of spectrum Saturn also emits blue and red light. Consequently, our eyes fail to see just green. So does Zubeneschamali actually look green? The only way to tell is to take a look yourself.  SEEN IT ZubENESchaMalI

4

1

CHArT And PHOTO: PeTe LAWrenCe

CHArT And PHOTO: PeTe LAWrenCe

1

2

2

M5

Our first port of call this month is the rather wonderful globular cluster known as M5. Located within the constellation of Serpens Caput, quite close to the border with Virgo, M5’s appearance an eyepiece is on a par with better-known M5 through M13 in Hercules. A small scope shows M5 to be Our first port of call this month is the rather condensed, withcluster a hint of star resolution at the edges. wonderful globular known as M5. LocatedAwithin the telescope constellationatof200x Serpens Caput, 6-inch magnification should be quite close to the border with Virgo, appearance capable of resolving the M5’s cluster to the core, revealing through an eyepiece is on a par with better-known many distinctive ‘strings’ of stars. This is one of the oldest M13 in Hercules. A small scope shows M5 to be globular known withatan age of condensed, with aclusters hint of star resolution the estimated edges. SEEN IT should be 13telescope billion years. A 6-inch at 200x magnification

5

capable of resolving the cluster to the core, revealing many distinctive ‘strings’ of stars. This is one of the oldest globular clusters known with an estimated age of 13 billion years.  SEEN IT

PaloMar 5

Our next target is also a globular cluster, but this one is at the other end of the brightness PaloMar 5 as Palomar 5, this globular appears scale. Known Our next target also aaglobular cluster, but and as such as little moreisthan smudge of light, this one is at the other end of the brightness is bestasseen with5,large aperture scopes or via imaging. scale. Known Palomar this globular appears hasthan magnitude butasissuch spread out, so its as littleItmore a smudgeof of +11.8 light, and is best seen with brightness large aperture or viait imaging. surface is scopes low. Find 2.3º to the southwest It has magnitude of +11.8 but is is spread so its by the gravitation of M5. The cluster being out, disrupted surface brightness is low. Find it 2.3º to the southwest of the Milky Way and there is evidence of streams of of M5. The cluster is being disrupted by the gravitation starsWay leaving it. For a while of it streams was thought to be a of the Milky and there is evidence of dwarfit.galaxy. it SEEN IT to be a stars leaving For a while was thought dwarf galaxy.  SEEN IT



6

3

ZubENESchaMalI

Continue south from Palomar 5 and you’ll reach the constellation of Libra and our next target – mag. +2.6 Zubeneschamali (Beta (β) Librae). This star is distinct because of reports that it appears One of the few deep-sky objects in the heart to have a green tint. If true, this makes it the only of Libra is globular cluster nGC 5897 – look greenish star in the sky visible to the naked eye. it 1.5º A star with peak output for in the greensoutheast part of the of mag. +4.5 Iota (ι) Librae. spectrum also emits bluenGC and red light.isConsequently, 5897 a broad, diffuse globular that can our eyes fail to see just green. Zubeneschamali only So be does partially resolved, but at mag. +8.6 is actually look green? The only way to tell is to take a considerably easier to identify than Palomar 5. look yourself.  SEEN IT

4

NGc 5897

The core looks quite uniform in brightness with no obvious central condensation. Brighter core stars NGc 5897 can be made out individually, but the many fainter One of the few deep-sky objects in the heart members merge together like a nebulous haze. of Libra is globular cluster nGC 5897 – look There is a notable triple pattern of mag. +11.5 to for it 1.5º southeast of mag. +4.5 Iota (ι) Librae. mag. +13.5 located north-northwest of the nGC 5897 is a broad, diffuse globularstars that can only be partially resolved, but at mag. +8.6 is SEEN IT cluster’s centre.

considerably easier to identify than Palomar 5. The core looks quite uniform in brightness with no obvious central condensation. Brighter core stars can be made out individually, but the many fainterchallenging object located There’s another members merge together like a nebulous haze. 3º to the southeast of nGC 5897, a mag. +11.6 There is a notable triple pattern of mag. +11.5 to nebula known as Merrill 2-1. This is a mag. +13.5 stars locatedplanetary north-northwest of the spot: the nebula is relatively faint, quite small cluster’s centre.  SEENtricky IT

5

MErrIll 2-1

and located extremely close to a mag. +11.2 star. There’s a mag. +9.9 star designated SAO 183407 There’s another challenging object located 50 arcseconds to the west that serves as a good 3º to the southeast of nGC 5897, a mag. +11.6 pointer to the area. Once you’ve found the nebula planetary nebula known as Merrill 2-1. This is a its close +11.2 star, don’t be afraid to tricky spot: the nebula isand relatively faint,mag. quite small pile to ona the At 150x magnification the and located extremely close mag.magnification. +11.2 star. There’s a mag. +9.9 starnebula designated willSAO start183407 to look like a slightly blurred star. 50 arcseconds to the west as ascope good at 200x magnification is needed A that 6- toserves 8-inch pointer to the area. Once you’ve found the nebula to show it convincingly.  SEEN IT

MErrIll 2-1

and its close mag. +11.2 star, don’t be afraid to pile on the magnification. At 150x magnification the nebula will start to look like a slightly blurred star. A 6- to 8-inch scope at 200x magnification is needed to show it convincingly.  SEEN IT final object is double Our

6

18 lIbraE

star 18 Librae. The primary star is a mag. +5.9 orange giant that lies 316 lightyears from the Sun. It is 18 lIbraE to Librae. locate, being the third point in a Our final object isfairly doubleeasy star 18 The primary star issquat a mag. +5.9 orange isosceles triangle that also includes giant that lies 316 lightyears from the Sun. It is Zubeneschamali (our third stop) and mag. +2.8 fairly easy to locate, being the third point in a Zubenelgenubi squat isosceles triangle that also includes (Alpha (α) Librae); the slightly brighter mag. Zubeneschamali (our third stop) and mag.+5.8 +2.8 Xi1 (ξ1) and mag. +5.5 Xi2 (ξ2) Zubenelgenubi (Alpha (α) Librae); thepoint slightlytoward it. A small scope will reveal Librae also +5.5 Xi brighter mag. +5.8 Xi1 (ξ 1) and 2 (ξ2 ) has a yellow, mag. +9.9 that themag. orange giant Librae also point toward it. A small scope will reveal -20look out companion 19.7 arcseconds away. Also that the orange giant has a yellow, mag. +9.9 for a third, mag. +11.5 star 162 arcseconds to the companion 19.7 arcseconds away. Also look out northeast of the primary.  SEEN IT for a third, mag. +11.5 star 162 arcseconds to the northeast of the primary.  SEEN IT

M5

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Binocular tour β

γ

γ

SERPENS CAPUT

γ

δ

mag.SERPENS +5.6 stars at each end of the chain are a CAPUT deeper yellow than the others, while the star next δ to the eastern end is almost white by comparison. You should find that the mag. +7.4 central star easily resolves into a triple star under dark skies or with larger binoculars.  SEEN IT

Explore the forgotten cousin of a famous mag. +5.6 stars at each end of the chainboöTIS are a 5 DElTa globular, a pair of giants and a starry chain deeper yellow than the others, while the star next

With ✓ Tick the box when you’ve seen each one Stephen Tonkin 

1 M92

Binocular tour 3

Our penultimate stop is another double

x by comparison. to the eastern end is almost10 white 50+7.4 star, mag. You should find that the mag. central star+3.5 delta (δ) Boötis. The primary is dark a deep easily resolves into a triple star under skiesyellow giant star nearly 60 or with larger binoculars.times  SEEN IT luminous than the Sun. Its yellowmore

Explore the forgotten cousin of aNu famous coroNaE borEalIS white, mag. +7.8 companion appears to be 105 5 DElTa boöTIS arcseconds away. delta Boötis is 117 lightyears Our tour starts with M92, a fine globular Line-of-sight double star nu (ν) globular, a pair of giants and a starry chain 15 x 10 x Ourinpenultimate stop is another double With70 cluster that suffers from its proximity to a 10 xsplit away, and its components are moving through 50 Coronae Borealis is an easy star, mag. +3.5 delta (δ) Boötis. The ✓ Stephen Tonkin  Tick the box when you’ve seen each one small binoculars, its distinct deep50 far more illustrious one. Start at the northwest yellow together. primary is a deep yellow space giant star nearly 60This confirms that they are a corner of the Keystone asterism in Hercules and components appearing a wide 6 arcminutes system: they have a separation of times more luminous thanbinary the Sun.star Its yellow1 imagine M92 a line heading northeast to mag.3 +3.8 Nu coroNaE white, mag. appears be 105 apart. TheborEalIS pair are remarkably similar, both+7.8 companion at least 0.6tolightyears and an orbital period starts with a fine Line-of-sight double star nu giants (ν) arcseconds is 117 lightyears 15Iota x Our (ι) tour Herculis. TwoM92, thirds of globular the way along being advanced with masses aboutaway. 2.5 delta Boötis 10 x this of at least 120,000 years.  SEEN IT 70 cluster that suffers from its proximity to a away, and its components are moving through 50 Coronae Borealis is an easy split in line, M92 shines at mag. +6.4; it has an times that of the Sun. The more northerly star, ν , 1 far more illustrious one. Start at the northwest small binoculars, its distinct deep yellow space together. This confirms that they are a apparent diameter about fifthand that ofcomponents the sits at 555 lightyears, just 10 lightyears corner of the Keystone asterism in one Hercules appearing a wide 6 arcminutes binary starfarther system: they haverV a separation of boöTIS imagine a line heading to mag.be +3.8 apart. The pairaway are remarkably both Moon. When younortheast find it, you’ll looking at the than ν2.similar, It is also a fractionatbrighter, shining and an orbital least 0.6 lightyears period The last stop on this month’s tour is Iotalight (ι) Herculis. Two of thirds of the way along masses 2.5 of at least than 120,000  xSEEN IT of a third a million stars. thisSEENbeing IT advanced at giants mag.with +5.2, 0.2 about magnitudes brighter ν2 years. 15 rV Boötis (also designated HIP 71644), 70 line, M92 shines at mag. +6.4; it has an times that of the Sun. The more northerly star, ν1, – a result of being about 750 million years which you can fnd 2.6° northeast of mag. apparent diameter about one fifth that of the sits at 555 lightyears, just 10 lightyears farther 6and rVtherefore boöTIS in its evolution Moon.M13 When you find it, you’ll be looking at the away than ν2. more It is alsoadvanced a fraction brighter, shining +3.6 rho (ρ) Boötis. rV is nearly midway last stop on this month’s tour is 15 x The and more luminous. IT light of a third of a million stars.  SEEN IT at mag. +5.2, larger 0.2 magnitudes brighter than ν2  SEEN between mag. +6.3 stars, the brightest HIPtwo 71644), 70 rV Boötis (also designated 10 x M92’s more renowned neighbour –isaM13, result of being about 750 million years which you can fnd 2.6° northeast mag. 50 which is called the ‘Great Cluster’ for good stars in ofthe feld of view of 15x70 binoculars. advanced inTau its evolution and therefore 2 reason. M13 Situated a third of the way downmore coroNaE +3.6 rho (ρ) Boötis. rV is nearly midway the It is a semi-regular variable with a period larger and more luminous.  SEEN IT more renowned neighbour is M13, between two mag. +6.3 stars, the brightest 10western x M92’s side of the Keystone asterism, it is visible borEalIS GrouP between 137 and 144 days, which changes 50 which is called the ‘Great Cluster’ for good stars in the feld of view of 15x70 binoculars. 4 Tau to theSituated nakeda eye evencoroNaE Move 4° to the northwest of nu Coranae in brightness from mag. +7.2 to mag. +9.8 reason. third in of a thereasonably way down thedark sky. It is a semi-regular variable with a period 10 x western of the Keystone asterism, it is +5.8 visible globular borEalIS GrouP 50 Borealis and you’ll come between with side small binoculars, this mag. to mag.137 +4.7 and 144 days, which changes – although recently it has only been falling to to the eye inina urban reasonably dark sky. even not 10 to the nu Coranae in brightness mag. +7.2 to mag. cannaked be seen skies, although nearly x Move 4°Tau (τ)northwest Coronaeof Borealis, the brightest in afrom very mag. +8.8,+9.8 so it remains well within reach of 50 Borealis and you’ll come to mag. +4.7 with small binoculars, this mag. +5.8 globular although recently it has only been falling to as splendidly as it appears in darker conditions. pretty straight chain (2.5° long)–of five stars binoculars. rV Boötis is a red star, in the latter can be seen in urban skies, although not nearly Tau (τ) Coronae Borealis, the brightest in a very mag. +8.8, so it remains well within reach of In 10x50s, it brightens towards the centre. M13 running east to west. All but the central star stage of evolution, as splendidly as it appears in darker conditions. pretty straight chain (2.5° long) of five stars binoculars. rV Boötis is a red star, in the latter on the giant branch of the contains over a million stars.  M13 SEEN IT running east toshine mag. notice that the on the Hertzsprung-russell diagram.  SEEN IT In 10x50s, it brightens towards the centre. west. brighter All but thethan central star +6.0. stage of evolution, giant branch of the contains over a million stars.  SEEN IT shine brighter than mag. +6.0. notice that the Hertzsprung-russell diagram.  SEEN IT

6

CHArTS And PICTureS: PeTe LAWrenCe

CHArTS And PICTureS: PeTe LAWrenCe

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STATISTICS

Moonwatch

TyPE: Crater SIZE: 213km wide aGE: 3.2 to 3.8 billion years old locaTIoN: Latitude 27.2°S, longitude 80.0°E bEST TIME To obSErVE: Two days after new Moon The sky guide APRIL 63 or one day after full Moon (1 and 2 April from 20:00 BST; 30 April and 1 May from 21:00 BST) N MINIMuM EquIPMENT: 10x binoculars

Humboldt

STATISTICS

Moonwatch Humboldt

TyPE: Crater SIZE: 213km wide aGE: 3.2 to 3.8 billion years old locaTIoN: Latitude 27.2°S, longitude 80.0°E bEST TIME To obSErVE: huMbolDTTwo N days after new Moon or one day after full Moon (1 and 2 April from 20:00 BST; 30 April and 1 May from 21:00 BST) MINIMuM EquIPMENT: 10x binoculars

“To give you a sense of E scale, Humboldt covers an area of 35,000 square km, which is about 1.5 “To give you a the sense of of Wales” times size

huMbolDT huMbolDT N

huMbolDT

scale, Humboldt covers about 5km deep. Under seen from above by orbiting an areabeing of 35,000 square good seeing conditions and the spacecraft, Humboldt displays right illumination these cliffs a delicate pattern of radial km, which is about 1.5 can be most impressive. The fractures that resembles a crater’s foor is largely fat, but spider’s web. These cracks are times the size of Wales” shows a variety of different very diffcult to see visually tones and textures. To give

from earth, but present a

being about 5km deep. Under seen from above by orbiting you aand sense scale, Humboldt good challenge if you’re into good seeing conditions the of spacecraft, Humboldt displays covers an area of 35,000 high-resolution imaging. right illumination these cliffs a delicate pattern of radial can be most impressive. fractures that resembles a Foreshortened regions of squareThe km, which is about 1.5 crater’s foor is largely aremoon can be very diffcult timesfat, thebut size ofspider’s Wales.web. These cracks the shows a variety of different very diffcult to see visually There is a central mountain to decode. between Petavius tones and textures. To give from earth, but present a complex and a curious curve and Humboldt lies 82km-wide you a sense of scale, Humboldt good challenge if you’re into smaller mountains and hills covers an area of of 35,000 high-resolution imaging.crater Legendre; many of the square km, whicharcing is aboutoff 1.5 to theForeshortened of northeast. Aregionssmaller craters between it and times the size of Wales. the moon can be very diffcult smaller, 15km-diameter crater Humboldt are catalogued as There is a central mountain to decode. between Petavius known as Humboldt N canlies be82km-wide being part of the Legendre complex and Humboldt a number of easily identifable features sit within humboldt’s rim – theseand a curious curve seen to the west, in the one notable exception of smaller the include a central peak complex, a mountain range and smaller craters mountains and hills crater Legendre; many offamily. arcing off to the northeast. A ofsmaller craters between itisand foreground, this curving the tormented 128km-wide Humboldt are catalogued as range.crater This crater and the crater Philips, which sidles up grips with. in order smaller, to see it15km-diameter CrATer HUmboLdT is known as Humboldt N can be being part of the Legendre a number of easily identifable sit within humboldt’s rim – these mountain range provide the to the west rim of Humboldt. convincingly the moon’s located in the zone offeatures libration seen to the west, in the family. one notable exception include a central peak complex, a mountain range and smaller craters most obvious visual features if the conditions are really right, as of this close to the eastern limb of the phase has to be just foreground, curving is the tormented 128km-wide rim. which sidles good, the to libration. As the This craterwithin moon.HUmboLdT The easiestisway to fnd range. and the Humboldt’s crater Philips, up see if you can fnd the grips with.does in order see it CrATer mountain range provide to the west Humboldt. convincingly the moon’s located in the zone of libration Lookthe carefully and it rim mayofbe 104km-wide crater barnard, crater is so close to the edge of it is to frst identify the more featuresto make if the conditions phase has the to bemoon, just right, close to the eastern limb of the182kmpossible out that theare really which sits against the southeast ouras view most of it obvious from visual favourably positioned, within Humboldt’s rim. good, see if you can fnd the does the libration. As the moon. The easiest way to fnd foor of the crater isn’t evenly rampart of Humboldt even earth foreshortens it into an wide crater Petavius. Look carefully and it may be 104km-wide crater barnard, crater is so close to the edge of it is to frst identify the more are pyroclastic nearer to the moon’s edge. be challenging Petavius lies 500km possible to make toned. out that There the which sits against the southeast the moon,ellipse. our viewitofcan it from favourably positioned, 182km-to the patches – dark deposits left to pull the crater out from the west of Humboldt, a distance foor of the crater isn’t evenly rampart of Humboldt evenover the coming months earth foreshortens it into an wide crater Petavius. toned. There are pyroclastic nearer activity to the moon’s edge. ellipse. it can be challenging Petavius lies 500km to the over from volcanic Humboldt’s position will get surrounding landscape, but that looks much smaller due patches – dark deposits left over the coming months to pull the crater out from the west of Humboldt, a distance – visible in certain parts of less favourable at the same vigilance reaps rewards. to foreshortening at the over from volcanic activity Humboldt’s position will get surrounding landscape, but that looks much smaller due the foor, most notably in the lunar phase, so make the most The crater’s rim is well moon’s edge. even knowing – visible in certain parts of less favourable at the same vigilance reaps rewards. to foreshortening at the southwest tophase, the west, the conditions during April defned some this fact, foor, most notably in the round lunar so make theof most rim isand welllined bythe moon’s edge. Humboldt even knowingcan stillThe crater’s southwest round to thein west, of the conditions duringto April lined steep by some this Humboldt can still and the northeast. see this amazing crater. rather cliffs, Humboldt befact, a tricky feature to get todefned and and in the northeast. to see this amazing crater. rather steep cliffs, Humboldt be a tricky feature to get to



E

64

Astrophotography Imaging Mars at opposition 64

ReCommended equIPmenT

need to try and complete the entire capture sequence in less than fve minutes. 8-inch or larger scope, Barlow lens, monochrome high frame rate camera, For a colour camera this isn’t too hard, RGB imaging flters mounted in a flter wheel but when trying to capture images using several flters it is more of a concern. Advanced processing techniques such as your fnal image derotation can be used to address motion will reveal the red blur, but there’s an easier solution that Planet’s large albedo hinges around the lack of signifcant detail surface features visible in the green flter – simply abstain from need to try and complete the taking entire a green-fltered image in the ReCommended equIPmenT capture sequence in less than fve minutes. frst place. it may sound crazy, but the green 8-inch or larger scope, Barlow lens, monochrome high frame rate camera, For a colour camera this isn’t too hard, image can be artifcially synthesised from RGB imaging flters mounted in a flter wheel but when trying to capture images using and blue results. The fnal colour several flters it is morethe of ared concern. will such lookasalmost identical to what Advanced processingimage techniques your fnal image derotation can be usedyou to address motion would have achieved using a full set of will reveal the red blur, but there’s an easier solution that rGb images, but you’ll reduce the time it Planet’s large albedo hinges around the lack of signifcant detail surface features needed for your capture sequence by a third. visible in the green flter – simply abstain Generating from taking a green-fltered image in thea synthetic green image also frst place. it may soundstreamlines crazy, but the the greencapture process, allowing image can be artifcially synthesised froma smooth sequence of you to generate the red and blue results. The fnal colour mars images for animation purposes. For image will look almost identical to what example, a run of rbrbrb captures would you would have achieved using a full set of to create an r(G)b result using rGb images, but you’llallow reduceyou the time it needed for your capturethe sequence by a pair third.– the parentheses indicate frst rb Generating a synthetic green that theimage greenalso is synthetic – then streamlines the capture process, allowing a second b(G)r result using the frst br you to generate a smooth sequence of pair.purposes. A third For r(G)b result would be created mars images for animation using the second example, a run of rbrbrb captures would rb pair, and so on. With you to create result using ‘relief’ features, these wouldallow normally be an r(G)b a fairly short time gap between r(G)b mArs is A bit of a tease as far as practical the frstcauses rb pair – the parentheses indicate revealed because height variation results, these can be animated together astronomy is concerned. After lurking in that the green is synthetic – then them to cast shadows, just like elevated to produce a smooth fowing rotation tricky parts of the sky and looking rather a second b(G)r result using the frst br structures close to the terminator do sequence this fascinating world. diminutive for many months, it bursts pair. A third r(G)b result would beofcreated martian back onto the scene for a short period, before on the moon. From earth, the using the second rb pair, and so on. With ‘relief’ features, these would normally be a fairly mArs is A bit of a tease as far as practical shadows are tiny and hard to pick short out, time gap between r(G)b fading into the background once again. revealed because height variation causes results, astronomy is concerned. After lurking in marscan be animated together This month it reaches opposition, so this so the main features of interest forthese them to cast shadows, just like elevated to produce a smooth fowing rotation tricky parts of the sky and looking rather imagers are albedodobased rather thanofrelief. is the best to bothitobserve image close to the terminator sequence this fascinating world. diminutive for time many months, bursts and structures SyNThETIc colourS Using a mono high frame rate camera it. Here, we’ll look at how to do the latter back onto the scene for a short period, before on the moon. From earth, the martian Although colour cameras are catching tiny and hard to pickmars’s out, refectivity fading the background oncerate again. rGb flters, withinto a mono high frame camerashadows and are and up, mono cameras still have the edge so the main features of interest for mars This month it reaches opposition, so this becomes quite interesting – the reasonTeChnIque for a set of rGb imaging flters. Key when it comes to planetary imaging. imagers are albedo based rather than relief. is the best time to both observe and image this is that the ‘information’ that passes colourS mars is a captivating astrophotography For a full-colour result from a mono SyNThETIc Using a mono high frame rate camera it. Here, we’ll look at how to do the latter through green flter gives very littlecolour cameras camera target because it is rate thecamera closestand world and we can Although are catching you need red, green and blue rGb flters, mars’sarefectivity with a mono high frame up, mono cameras still have the edge extra image–detail than seeofthat reasonable earth, quite imaging filters; this significantly reduces interesting the reason forcan be obtained a set rGb has imaging flters. similarity to becomes when it comes to planetary imaging. colour-related problems such as chromatic is that the ‘information’ that passes mars is aitcaptivating astrophotography with red and blue flters alone.ForThis in that shows both surface featuresthis and a full-colour result from a mono through a green flter gives very little target because it is the closest world we can aberration and atmospheric dispersion. camera you need red, green and blue surprising fact can be used to help weather. From earth we can see brighter see that has reasonable similarity to earth, extra image detail than can be obtained imaging filters; this significantly reduces filtered sequences take Unfortunately, overcome one of the main issues when deserts, darker rock and gleaming polar colour-related problems such as chromatic with red and blue flters alone. This in that it shows both surface features and longer to complete and overly long rGb imaging a relatively fast rotating aberration and atmospheric dispersion. caps. These are ‘albedo features’; they are surprising fact can be used to help weather. From earth we can see brighter capture may result in motion blur – but Unfortunately, filtered sequences take planet as mars: too long visible because they have notably different overcome one of the such main issues whenif you take deserts, darker rock and gleaming polar usinglong a synthetic green capture can longer to complete and overly rGb imaging a relatively fast rotating caps. These are ‘albedo features’; they are to collect an image set, the fnal rGb may refectivity (albedo) to adjacent areas. help. capture may result in motion blurFind – butout how in the step-by-step. mars:motion if you take tooFor longthis reason, visible because they have notably different planet such as using a synthetic green capture can show blur. you Features such as craters, mountains and to collect an image set, the fnal rGb may refectivity (albedo) to adjacent areas. help. Find out how in the step-by-step. valleys are much harder to image show motion blur. For this reason, you Features such as craters, mountains and from earth of their small apparent size valleys arebecause much harder to image from  Send your image to: [email protected] earth because of their small apparentKnown size at the planet’s vast distance. as Send your image to: [email protected]

Astrophotography Imaging Mars at opposition

ALL PICTureS: PeTe LAWrenCe

ALL PICTureS: PeTe LAWrenCe

Key TeChnIque

at the planet’s vast distance. Known as






STeP-By-STeP GuIde


STeP-By-STeP GuIde sTep 1 Mars has an apparent diameter of 15 arcseconds at opposition, so you’ll need a decent image scale to show much detail. as a guide, aim for a focal ratio of between f/15 and f/45, adjusted by using optical amplifers such as a barlow lens. only use a high image scale if the seeing is good.

sTep 1 Mars has an apparent diameter of 15 arcseconds at opposition, so you’ll need a decent image scale to show much detail. as a guide, aim for a focal ratio of between f/15 and f/45, adjusted by using optical amplifers such as a barlow lens. only use a high image scale if the seeing is good.

sTep 2 With Mars on chip, select the red flter and focus as quickly and accurately as possible. aim to collect 2,000-3,000 frames, although try to avoid imaging for more than 90 seconds per flter. adjust the camera gain and frame rate if necessary to maximise the saturation level for each flter to around 80-90 per cent.

sTep 3 Switch to your blue flter, quickly re-focus and capture the blue image. repeat the rb sequence as many times as required. When done, load each capture into a stacking program, such as the freeware regiStax, and process each through to wavelet sharpening. apply a subtle amount of wavelet sharpening to the end result as required. sTep 3 Switch to your blue flter, quickly re-focus and capture the blue image. repeat the rb sequence as many times as required. When done, load each capture into a stacking program, such as the freeware regiStax, and process each through to wavelet sharpening. apply a subtle amount of wavelet sharpening to the end result as required.

sTep 2 With Mars on chip, select the red flter and focus as quickly and accurately as possible. aim to collect 2,000-3,000 frames, although try to avoid imaging for more than 90 seconds per flter. adjust the camera gain and frame rate if necessary to maximise the saturation level for each flter to around 80-90 per cent.

sTep 4 load an rb pair into a layer-based editor as separate layers. adjust the upper image so that it is aligned with the lower one. crop to remove any whites edges this creates. Duplicate the r and b layers and move to the top of layer stack. Make top layer 50 per cent transparent and merge with the one below – this creates the synthetic green.

sTep 4 load an rb pair into a layer-based editor as separate layers. adjust the upper image so that it is aligned with the lower one. crop to remove any whites edges this creates. Duplicate the r and b layers and move to the top of layer stack. Make top layer 50 per cent transparent and merge with the one below – this creates the synthetic green.

sTep 5 create a blank rGb image with the same dimensions as the sTep 6 Switch to the layers list and duplicate the base r(G)b layer to image you were working on in step 4. copy the r image layer to the red make your fnal tweaks. If the colour looks off or subdued, try using sTep 5 create image with the same dimensions as the sTep 6 Switch to the layers list and duplicate the base r(G)b layer to channel in thea blank blankrGb image. repeat for the (G) and b layers, pasting them the program’s auto-colour function; if the colours look too strong after image you were working on in step 4. copy the r image layer to the red make your fnal tweaks. If the colour looks off or subdued, try using into their respective green and blue channels. The result should be a full this, tryfunction; fadingifthe back a bit. adjust the fnal levels, contrast channel in the blank image. repeat for the (G) and b layers, pasting them the program’s auto-colour the auto-colour colours look too strong after colour r(G)b image showing the distinctive colours of Mars. and brightness to taste. apply sharpening into their respective green and blue channels. The result should be a full this, try fading the auto-colour back a bit. adjust the fnal levels, contrastsparingly. colour r(G)b image showing the distinctive colours of Mars.

and brightness to taste. apply sharpening sparingly.



Dark skies

RECOGNISED Dark skies As two more sites in northern England and Scotland earn Dark Sky status, Paul F Cockburn hears how they achieved the award

RECOGNISED L

Island of Sark and Exmoor National and affect human health. One ongoing ight pollution has been a Park followed suit in 2011, then Brecon response has been the identifcation, growing problem for the past Beacons National Park in early 2013. recognition and protection of areas century, which has seen our December 2013 saw two more, bringing around the world that are still largely view of the night sky obscured the UK’s total to six: Northumberland free of signifcant light pollution. by the glow of artifcial lighting. National Park joined with neighbouring It started in 2006, when the US-based Since 2003, the annual International Kielder Water and Forest Park to create International Dark Sky Association Dark Sky Week – this year’s is 20-26 established a programme to classify Dark a single Dark Sky Park, and the Island April – has become an umbrella for Island of Sark and Exmoor National and affect human health. Reserves One ongoing pollution been a not just of of Coll in Scotland became a Dark Sky Parks, and Communities. eventsight that remindhas people the Park followed suit in 2011, then Brecon response has been the identifcation, growing problem for the past Sky Community. We spoke to some Galloway Forest Park in Scotland was wonder and beauty above their heads, Beacons National Park in early 2013. recognition and protection of areas century, which has seen our of the people who made these latest the frst area in the UK to ft the bill, but also how light pollution can disrupt December 2013 saw two more, bringing around the world that are still largely view of the night sky obscured designations possible. attaining Dark Sky status in 2009; the to six: Northumberland natural environment, the UK’s total free of signifcant light pollution. bythe the glow of artifcial lighting. waste energy

KILEDER WATER AND FOREST PARK

KILEDER WATER AND FOREST PARK

As two more sites in northern England and Scotland earn Dark Sky status, Paul F Cockburn hears how they achieved the award

L

Since 2003, the annual International Dark Sky Week – this year’s is 20-26 April – has become an umbrella for events that remind people not just of the wonder and beauty above their heads, but also how light pollution can disrupt the natural environment, waste energy

It started in 2006, when the US-based International Dark Sky Association established a programme to classify Dark Sky Parks, Reserves and Communities. Galloway Forest Park in Scotland was the frst area in the UK to ft the bill, attaining Dark Sky status in 2009; the

National Park joined with neighbouring Kielder Water and Forest Park to create a single Dark Sky Park, and the Island of Coll in Scotland became a Dark Sky Community. We spoke to some of the people who made these latest designations possible.

The success of Kielder Observatory made applying for Dark Sky status a natural step

The success of Kielder Observatory made applying for Dark Sky status a natural step

ABOUT THE WRITER ABOUT THE WRITER Paul F Cockburn is a freelance journalist who has been writing about science and technology – past and future – since 1996.

Paul F Cockburn is a freelance journalist who has been writing about science and technology – past and future – since 1996.

68

Northumberland National Park TONY GATES Chief executive

Comet Hale-Bopp shines bright in the darkness of Northumberland National Park

“Tranquility has been recognised as one of the main special qualities 68of Northumberland National Park,” says chief executive Tony Gates. “That sense of the unspoilt, which is something that we know residents and visitors really value, we felt also extended to the skies.” TONY GATES So, whenChief applying for Dark Sky Park executive status, Gates believes they started from “Tranquility has been a very goodrecognised base. “We needed to change as one of the very little really,” he says. “The survey main special qualities our existing National skies, which of of Northumberland Park,” was part of says chief executive Tony Gates. we “That the application, showed already had sense of the unspoilt, which is a very high level of darkness, which led something that we know residents tovisitors us being designated and really value, we feltgold also status. “Our extended to intention the skies.” was always to ensure So, applying Dark Sky Park skies we when protected theforlevels of dark status, Gates believes they started from and, where there were opportunities a very good base. “We needed to change to enhance them, that we did,” Gates very little really,” he says. “The survey “What we’ve found through this of adds. our existing skies, which was part of is that people have really theprocess application, showed we already had come a very high levelit’s of really darkness, which into led just on board: tapped

ALAMY, KILEDER WATER AND FOREST PARK, WILL GATER, ALEx SPEED

ALAMY, KILEDER WATER AND FOREST PARK, WILL GATER, ALEx SPEED

Northumberland National Park

to us being designated gold status. “Our intention was always to ensure we protected the levels of dark skies and, where there were opportunities to enhance them, that we did,” Gates adds. “What we’ve found through this process is that people have really come on board: it’s really tapped into just

Comet Hale-Bopp shines bright in the darkness of Northumberland National Park

how much they value the dark skies. We had people voluntarily adjusting the angles of outdoor spotlights, adjusting the fttings.” Adding weight to Northumberland National Park’s application was the fact that it was jointly made with neighbouring Kielder Water and Forest

how much they value the dark skies. We had people voluntarily adjusting the angles of outdoor spotlights, adjusting the fttings.” Adding weight to Northumberland National Park’s application was the fact that it was jointly made with neighbouring Kielder Water and Forest

Park. “In their case the application was largely driven by the popularity of the Kiedler Observatory and the sudden realisation that the dark skies were really widely valued,” says Gates. “It just so happened that the two parks were working on this idea at the same time, so we decided to put our lot together.”

Park. “In their case the application was largely driven by the popularity of the Kiedler Observatory and the sudden realisation that the dark skies were really widely valued,” says Gates. “It just so happened that the two parks were working on this idea at the same time, so we decided to put our lot together.”

Kielder Water and Forest Park

Kielder Water and Forest Park A sycamore stands alone against the starry skyscape over Kielder

HEIDI MOTTRAM Chairperson A sycamore stands

The initial

development in the area, as a minor – a large part of the park Quite early on, the trust alone against the starry way of helping ensure it remains is uninhabited anyway.” skyscape over Kielder linked up with the application a vibrant, living community. She adds that the engagement being made by neighbouring Dark Sky status “The idea as really came from ofoflocal communities been The initial development in the area, a minor – a large part the park Quitehas early on, the trust Northumberland National was simple, way of helping the Kielder and great. “At one primary Park. “In many respects, that inspiration ensure it Observatory remains is uninhabited anyway.” linked up school, with the application behindaccording attaining toa vibrant, living community. She“The adds that thethe engagement being made just grew,” says Mottram. children really got intobyitneighbouring and way of working is embedded Dark Sky status really came from became of local communities has been coversNorthumberland National here,” Mottram says. chair of the “The idealocal community quite designed for the school’s was simple, the Kielder Observatory and great. “At one primary school, Park. “In many respects, that Kielder Water and Forest Park about“The it. At one unshielded says. is embedded “People in these communities according to just grew,” excited says Mottram. thelevel children really got into it andlights,” wayshe of working Development Trust, Heidi I thinkbecame we already that covers for“They really embraced the whole recognise that because they’re chair of the local community quite knew designed the school’s here,” Mottram says. Kielder Water–and Forestthe Park At one says.One of the “People these communities Mottram it was success excited about theit.sky waslevel stunning, unshielded that we lights,” she thing. villagesin has so small on their own, it’s Development Trust, Heidi knew that asset, “They recognisewith that because of the Kielder Observatory, I think we already had a fabulous that itreally embraced hadthe itswhole lights replaced LED they’re often diffcult to do anything. Mottram – it was the success the sky was stunning, that we thing. One of the villages has so small on their own, it’s opened in 2008. was pretty dark and that the units – there have been some The two parks are side by side; of the Kielder Observatory, had a fabulous asset, that it had its lights replaced with LED often diffcult to do anything. The trust has long been looking changes required by the changes, but nothing I would it was obvious we should opened in 2008. was pretty dark and that the units – there have been some The two parks are side by side; for trust newhas ways promote lighting were generally describe The longtobeen lookingeconomic changes required by audits the changes, but nothing I would as massive.” it was obvious we should work together.”

HEIDI MOTTRAMinspiration Chairperson behind attaining

for new ways to promote economic

lighting audits were generally



describe as massive.”

work together.”

dark sky sites april 69

Galloway was the frst Dark Sky place in the UK, earning its award in 2009

Galloway was the frst Dark Sky place in the UK, earning its award in 2009

they did not ft in anything except Community because they were protected by natural boundaries; they didn’t really have a buffer zone to make either a Reserve. “Some areas that aren’t surrounded by water have that same issue,” he adds. “If they are surrounded by public land, they sometimes can’t really incorporate dark sky sites april 69 that into the equation as a buffer zone because there isn’t a township or local authority in the area that’s able to they did not ft in anything except sign a declaration of intent to abide Community because they were protected our guidelines. by natural boundaries;by they didn’t really have a buffer zone to make either a Reserve. “Some areas that aren’t surrounded “We don’t look for quantities of by water have that same issue,” he adds. designation; we’re not looking to have “If they are surrounded by public land, hundreds of these,” Parks insists. they sometimes can’t really incorporate “Any decision that into the equation as a buffer zone is based on the merits because there isn’t a township or local of the application. What we look for authority in the area that’s able to is extraordinary dedication to the sign a declaration of intent to abide preservation of that area in the future. by our guidelines.

It’s not all about darkness

It doesn’t matter whether the area is

It’s not all about darkness as dark as it possibly can be; what

International Dark Skies Association

“We don’t look for quantities of we’re looking for is a community that’s designation; we’re not looking to have willing to make the changes and have hundreds of these,” Parks insists. dedication to try to preserve that “Any decision is based the on the merits forwethe next of the application. What look for generation. is extraordinary dedication to the applications take a long “These preservation of that area in the time to future. prepare: they’re not easy,” It doesn’t matter whether the area is he adds. “Some people get into them as dark as it possibly can be; what The association is also introducing and then that’s fnd out pretty quickly that we’re looking for is a community BOB PARKS a category called Development of to make the changes willing theseand arehave not a quick path to fame Executive director dedication preserve that Different countries now Distinction. “That’s one stepthe down the to try toand fortune. for the next generation. chain for residential developments that want to have their own Dark Sky “We stared out with “These applications take a long may not be a town or city, but have an they’reParks, but the level of cooperation just two designations time to prepare: not easy,” interest in protecting the development. and collaboration required to get – Reserve and Park,” he adds. “Some people get into them The association also introducing then fnd out pretty that We’reisactually looking now and at another allquickly the different parties to agree to says Bob Parks, executive director of the BOB PARKS a category called Development ofmodifying current these are not a quick path to fame is diffcult. It takes a designation, or something International Dark Skies Association. Executive director Distinction. “That’s one step down the and fortune. Different countries now ones. For example, two islands are part sustained effort by a community over “Then we added Community. The system chain for residential developments that want to have their own Dark Sky “We stared out with of the programme, and in both cases a long period of time.” evolves over time to take account of may not be a town or city, but have an Parks, but the level of cooperation just two designations the types of areas where people are interest in protecting the development. and collaboration required to get – Reserve and Park,” We’re actually looking now at another all the different parties to agree to says Bob Parks, executive director of the interested; we’re fnding, as we continue The UK now boasts six Dark designation, or modifying current something is diffcult. It takes a Sky places, the others being Sark, International Dark Skies Association. to expand the programme, that one ones. For example, two islands are part sustained effort by a community overExmoor and – shown here – the “Then we added Community. The system size defnitely doesn’t ft all, so we’reof the programme, and in both cases a long period of time.” evolves over time to take account of Brecon Beacons make adjustments.” thetrying types oftoareas where people are interested; we’reare fnding, as we continue So what the current technical The UK now boasts six Dark Sky places, the others being Sark, to distinctions expand the programme, betweenthat theone different kinds Exmoor and – shown here – the size defnitely doesn’t ft all, so we’re of Dark Sky places? “Starting at the Brecon Beacons trying to make adjustments.” larger end of the spectrum, a ‘Reserve’ So what are the current technical is not required protected distinctions between to thebe different kindsby a of government Dark Sky places? “Starting at thesays. “You can entity,” Parks larger end ofathe spectrum, a ‘Reserve’ develop Reserve around any property is not required to be protected by a that the community and residents government entity,” Parks says. “You can are interested in protecting. A ‘Park’ develop a Reserve around any property specifcally has to have public protection, that the community and residents arewhich interested in protecting. A ‘Park’ also ensures it’s not private specifcally has to have public protection, ESA’s JUICE mission, due to land. On the municipal end of the which also ensures it’s not private launch in 2022, will study spectrum, ‘Community’ ESA’s JUICE mission, due to land. On the municipal end of theis for the Galilean moons in greater launch in 2022, will study townships and cities, places that spectrum, ‘Community’ is for detail than ever before the Galilean moons in greater townships and cities, places that are incorporated entities.” detail than ever before are incorporated entities.”

International Dark Skies Association



70 dark sky sites april

Isle of Coll

Coll is Britain’s second Dark Sky Community

OLvIN SMITH Amateur astronomer

“An International Dark Sky Community is a town, city, municipality, 70ordark sky sites april other legally organised community that shows what the International Dark Sky Association describes as ‘exceptional Coll is Britain’s dedication’ to preserving the night sky,” second Dark explains amateur astronomer Olvin Smith, Sky Community who lives on the Inner Hebridean island OLvIN SMITH of Coll – since December 2013 the second Amateur astronomer Dark Sky Community in Britain. “An International Dark “It started around two years ago when Sky Community is a fellow astronomer Oliver saw that Sark town, city,Tony municipality, status and thought or had otherbeen legallyawarded organisedthe community that shows the International DarkSmith says. that wewhat should get it as well,” Sky Association describes as ‘exceptional commitment from some people to change around the island. “On several sites I got “This led to a meeting which ended up dedication’ to preserving the night sky,” their outside lights to correct type,” Smith readings of 21.9 [magnitudes per square with a core group of four – myself, Tony, explains amateur astronomer Olvin Smith, notes. “We also needed to get the council hotel JulieHebridean Oliphantisland and guest house arcsecond], which make our skies some of who livesowner on the Inner of owner Coll – since December 2013taking the second to endorse our lighting plan.” Paula Smalley it forward. We the darkest in Europe,” he says. “Once we Dark Sky Community in Britain. It’s been very much a ‘ground up’ got in touch with the association, and had a had all the data, and with the help of a dark “It started around two years ago when affair, Smith insists. “The community couple of phone calls with chief executive Bob skies consultant, Tony put together our fellow astronomer Tony Oliver saw that Sark has done all the work without any outside application, which was fnished last May. Parks, who talked us through the process. had been awarded the status and thought funding; the money and work came “We had to alter some of the lights to Having a Unihedron that we shouldpurchased get it as well,” Smith says. [sky quality] commitment people change around the island. several sites I got “This led toSmith a meeting which ended up survey from thetoislanders.” make“On them point straight down and getfrom some meter, completed a light

COLL DARK SKY GROUP

COLL DARK SKY GROUP

Isle of Coll

with a core group of four – myself, Tony, hotel owner Julie Oliphant and guest house owner Paula Smalley taking it forward. We got in touch with the association, and had a couple of phone calls with chief executive Bob Parks, who talked us through the process. Having purchased a Unihedron [sky quality] meter, Smith completed a light survey

readings of 21.9 [magnitudes per square arcsecond], which make our skies some of the darkest in Europe,” he says. “Once we had all the data, and with the help of a dark skies consultant, Tony put together our application, which was fnished last May. “We had to alter some of the lights to make them point straight down and get

Visiting the UK’s Dark Sky sites

their outside lights to correct type,” Smith notes. “We also needed to get the council to endorse our lighting plan.” It’s been very much a ‘ground up’ affair, Smith insists. “The community has done all the work without any outside funding; the money and work came from the islanders.”

Visiting the UK’s Dark Sky sites

1 Brecon Beacons National Park Arinagour, Isle of Coll, PA78 6SZ International Dark Sky Reserve 01879 230334 National Park Visitor Centre [email protected] Libanus, Brecon, Powys, LD3 8ER http://darkskies.visitcoll.co.uk 01874 623366 www.beacons-npa.gov.uk/contact-us 5 Northumberland National Park 1 Brecon Beacons National Park Arinagour, Isle of Coll, PA78 6SZ www.beacons-npa.gov.uk and Kielder Water and Forest4Park International Dark Sky Reserve 01879 230334 International Dark Sky Park National Park Visitor Centre [email protected] 2 Exmoor Park Once Brewed Visitor Centre Libanus, Brecon,National Powys, LD3 8ER http://darkskies.visitcoll.co.uk 01874 623366 International Dark Sky Reserve Military Road, Bardon Mill, Hexham, NE47 7AN www.beacons-npa.gov.uk/contact-us 5 Northumberland Park Dulverton National Park Centre 01434National 344396 www.beacons-npa.gov.uk and Kielder Water and Forest Park 7-9 Fore Street, Dulverton, TA22 [email protected] Dark Sky Park 3 01398 National 323841Park 2 Exmoor Once Brewedwww.northumberlandnationalpark.org.uk Visitor Centre [email protected] International Dark Sky Reserve Military Road, Bardon Mill, Hexham, NE47 7AN Dulverton National Park Centre 01434 344396 www.exmoor-nationalpark.gov.uk Kielder Observatory 7-9 Fore Street, Dulverton, TA22 9EX [email protected] Black Fell, Off Shilling Pot, Kielder, NE48 1EJ 01398 323841 www.northumberlandnationalpark.org.uk 3 Galloway Forest Park 07805 638469 [email protected] International Dark Sky Park [email protected] www.exmoor-nationalpark.gov.uk Kielder Observatory Black Fell, Offwww.kielderobservatory.org Shilling Pot, Kielder, NE48 1EJ Galloway Astronomy Centre 3 Galloway Forestmiles Park east of Monreith 07805 638469 A747, three International Dark Sky Park [email protected] 01988 500594 6 Isle of Sark Galloway Astronomy Centre www.kielderobservatory.org 1 [email protected] International Dark Sky Community A747, three miles east of Monreith www.forestry.gov.uk/darkskygalloway 01988 500594 6 Isle of Sarkwww.sark.co.uk [email protected] International Sark Dark Sky Community Tourist Offce 2 www.forestry.gov.uk/darkskygalloway www.sark.co.uk 4 Isle of Coll The Avenue, Sark Island, GY10 1SA Sark Tourist Offce International Dark Sky Community The Avenue, 01481 832345 4 Isle of Coll Sark Island, GY10 1SA c/o The Coll Hotel [email protected] International Dark Sky Community 01481 832345 c/o The Coll Hotel



[email protected]

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SP ED EC IT IA IO L N SP ED EC IT IA IO L N

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Two centuries after Fraunhofer Two centuries after discovered darkFraunhofer lines in the Sun’s discovered lines in the looks Sun’s at the spectrum,dark Will Gater spectrum, Will Gater looks at the next generation of spectroscopes next generation of spectroscopes

this light can tell them, astronomers must turn >

thinkstock, alamy

The SecreTS oF

thinkstock, alamy

unlocking E The SecreTS oF unlocking E

very day, as Earth’s terminator sweeps around the globe, the Sun sets in some part of the world and the blue sky deepens. On mountaintops and high desert plateaus, domes open and motors whirr very day, as terminator asEarth’s various kinds ofsweeps astronomical machinery around the globe, the Sun sets in some heaves into life. housed in observatories part of the world and the blue sky Like the coral polyps that emerge at night to deepens. On mountaintops and high feed, the telescopes inside these observatories desert plateaus, domes open and motors whirr as various kinds of astronomical machinery are on the hunt for passing quarry. Yet they seek housed in observatories heaves into something farlife. more exotic than even the most Like the coral polyps that emerge at night to unusual plankton: photons of celestial light. feed, the telescopes inside these observatories Photons thatYet may have are on the hunt for passing quarry. they seekbeen travelling for billions years across unimaginably vast stretches of something far moreof exotic than even the most unusual plankton: photons celestialthat, light. crucially, can reveal the space. of Photons Photons that may have been travelling for billions secrets of the objects they’ve come from. of years across unimaginably vast stretches of As they peer out into space, the huge mirrors space. Photons that, crucially, can reveal the the world’s professional telescopes catch some secrets of the objectsofthey’ve come from. of these precious photons. Sensitive cameras can As they peer out into space, the huge mirrors of the world’s professional telescopes catch somebe, producing pictures record the light if need of these precious photons. Sensitive cameras can of stars, nebulae and galaxies that enable record the light if need be, producing pictures to piece together the story of their of stars, nebulae andastronomers galaxies that enable But to delve deeper into what astronomers to piecedistant togethersubjects. the story of their distant subjects. Butthis to delve deeper what astronomers must turn > light can into tell them,

74

Joseph von Fraunhofer, left, demonstrates his spectrocope in Munich in 1814

74

Joseph von Fraunhofer, left, demonstrates his spectrocope in Munich in 1814

> to another, less celebrated, tool of astronomical

discovery – the spectrograph. The realisation that light could harbour information about celestial objects came thanks to the work of the German glass-maker Joseph von Fraunhofer. In 1814 he dispersed the Sun’s light into a rainbow of colours – known as a spectrum > to another, less celebrated, tool of astronomical – discovering numerous dark absorption lines (see discovery – the spectrograph. ‘The Science of that were later found The realisation thatSpectra’, light couldright) harbour information celestial objectsof came to betrayabout the composition ourthanks star. With the to subsequent the work of thedevelopment German glass-maker Joseph von to view – of spectroscopes Fraunhofer. In 1814 he dispersed the Sun’s light and spectrographs to record – celestial spectra and into a rainbow of colours – known as a spectrum the lines they contained, astronomers had a means – discovering numerous dark absorption lines (see to Science examine the make-up of were stars. ‘The of Spectra’, right) that later found alamy x 3, n.a.sharp/noao/nso/kitt peak Fts/aUra/nsF, eads astriUm, thinkstock

alamy x 3, n.a.sharp/noao/nso/kitt peak Fts/aUra/nsF, eads astriUm, thinkstock

to betray the composition of our star. With the subsequent development of spectroscopes to view – and spectrographs to record – celestial spectra and those early days, spectroscopy theEver linessince they contained, astronomers had a means and the spectrograph have been an integral part of to examine the make-up of stars.

The next generation

Þ Lines in the Sun’s mirror segments sit protected within huge polished spectrum show which metal containers. Gradually, the components astronomical research, giving astronomers insights wavelengths of light The generation are being meticulously tested and, eventually, intonext not just the composition of faraway bodies have been absorbed by Ever since those early days, spectroscopy and integrated into the telescope’s skeleton, ahead of but also their temperature, distance and even its atmosphere Þ Lines in the Sun’s mirror segments sit protected within huge polished the spectrograph have been an integral part of its planned launch in 2018. movements. Now, two centuries after Fraunhofer’s spectrum show which metal containers. Gradually, the components astronomical research, giving astronomers insights wavelengths of light in eventually, its own corner of the Goddard clean studies, readying a new generation are being meticulously Sitting tested and, into not just astronomers the compositionare of faraway bodies have been absorbed by integrated into the telescope’s skeleton, ahead butofalso their temperature, distance the and even room, NIRSpec – theofNear-Infrared Spectrograph spectrographs to explore Universe, theitslikes atmosphere its planned launch in 2018. movements. Now, two centuries after Fraunhofer’s – is just one of the four instruments that will of which have never been seen before. Sitting in its own corner of the Goddard clean studies, astronomers are readying a new generation fy on James Webb. As with all of the telescope’s Under the bright lights of the cavernous High Bay room, NIRSpec – the Near-Infrared Spectrograph of spectrographs to explore the Universe, the likes instruments, it will room at NASA’s – is just one of the four instruments that willfocus on observing the Universe of clean which have never been seenGoddard before. Space Flight Center at infrared wavelengths. in Maryland, the James Webb Space Telescope is fy on James Webb. As with all of the telescope’s To understand why, you Under the bright lights of the cavernous High Bay instruments, it will focus observing theat Universe clean room at NASA’s Goddard Space Flight Center onlyon need to look the work of James Webb’s slowly taking shape. Yellow scissor fences carefully at infrared wavelengths. To understand why, you in Maryland, the James Webb Space Telescope is forebear, the Hubble Space Telescope. partition off areas of the immaculate, white-foored only need to look at the work of James Webb’s slowly taking shape. Yellow scissor fences carefully Hubble has excelled at studying faraway galaxies room where instruments and other structures rest forebear, the Hubble Space Telescope. partition off areas of the immaculate, white-foored asatwell as extrasolar planets and how they form on where substantial support stands. High rest above, on an Hubble has excelled studying faraway galaxies room instruments and other structures as well as extrasolar planets how they form onenormous substantial support on an 18 primary withinand vast clouds of dust and gas. But to peer gantry,stands. each High of theabove, telescope’s within vast clouds of dust and gas. But to peer enormous gantry, each of the telescope’s 18 primary skyatnightmagazine.com 2014


stellar spectroscopy april 75

The science of spectra Key to understanding why spectroscopy is colours from violet at one end to red at the In emission lines you see the opposite. For such a formidable tool for astronomers is other. Yet when we look at stars within this example, photons from a bright star may be knowing what creates the features of a continuum we see dark lines, like those that causing a nearby nebula to glow. When this spectrum. You can think of the lines in Fraunhofer saw in the spectrum of the Sun. happens, the photons from the star give astronomical spectra as celestial fngerprints, These are absorption lines. They’re made energy to, or ‘excite’, the electrons in the in that they can help scientists work out what when photons of light passing through the nebula’s gases. Those electrons will eventually atoms and molecules created them. star’s atmosphere interact with electrons in settle down and they do this by releasing stellar spectroscopy april 75 These ‘fngerprints’ come in two forms, the gases there. These electrons can absorb energy in the form of a photon of light. The absorption lines and emission lines. Let’s look the photons’ energy, removing certain wavelengths of the photons emitted are at absorption lines frst. Objects such as stars wavelengths from the continuum. Which ones indicative of the atom or molecule that is create what are known as continuum spectra. are removed depends on the atoms or glowing. If you could observe the light from If we think about just the visible-light portion molecules present. By identifying the dark the nebula with a spectroscope, you’d see a of the electromagnetic spectrum, a continuum lines in a spectrum astronomers can determine series of thin, bright lines of different colours Keyspectrum to understanding why an spectroscopy is rainbow colours at one end to red at the In emission lines you see the opposite. For looks like unbroken of from violet the composition of the star’s atmosphere. – these are emission lines.

The science of spectra such a formidable tool for astronomers is knowing what creates the features of a spectrum. You can think of the lines in astronomical spectra as celestial fngerprints, in that they can help scientists work out what atoms and molecules created them. These ‘fngerprints’ come in two forms, absorption lines and emission lines. Let’s look at absorption lines frst. Objects such as stars create what are known as continuum spectra. If we think about just the visible-light portion of the electromagnetic spectrum, a continuum spectrum looks like an unbroken rainbow of

other. Yet when we look at stars within this continuum we see dark lines, like those that Fraunhofer saw in the spectrum of the Sun. These are absorption lines. They’re made when photons of light passing through the star’s atmosphere interact with electrons in the gases there. These electrons can absorb the photons’ energy, removing certain wavelengths from the continuum. Which ones Star’s are removed depends on theatmosphere atoms or molecules present. By identifying the dark lines in a spectrum astronomers can determine the composition of the star’s atmosphere.

example, photons from a bright star may be causing a nearby nebula to glow. When this happens, the photons from the star give energy to, or ‘excite’, the electrons in the nebula’s gases. Those electrons will eventually settle down and they do this by releasing energy in the form of a photon of light. The wavelengths of the photons emitted are indicative of the atom or molecule that is glowing. If you could observe the light from the nebula with a spectroscope, you’d see a series of thin, bright lines of different colours – these are emission lines.

Hot bright stars

NEBULA

STAR

Hot bright stars

Star’s atmosphere

NEBULA

STAR

ABSORPTION LINES

EMISSION LINES

further out into the Universe and deeper into nebulae you need to see the cosmos at much longer ABSORPTION LINES wavelengths, says NIRSpec instrument scientist James Muzerolle. “Near-infrared and mid-infrared further out into theallow Universe andpenetrate deeper intothe dusty observations us to nebulae you need to that see the cosmos much longer environments are very at important for studying wavelengths, says NIRSpec instrument scientist star and planet formation,” he says. James Muzerolle. “Near-infrared and mid-infrared Using NIRSpec, astronomers will also be able to observations allow us to penetrate the dusty study lightthat from some of the most distant, and thus environments are very important for studying star and planet formation,” he says. earliest, galaxies. Light that has been stretched as it Using NIRSpec, astronomers will alsoUniverse. be able to “The light travelled across the expanding study light from some of the most distant, and thus that we’ll measure at our telescope will be light that earliest, galaxies. Light that has been stretched as it was originally mostly inUniverse. the ultraviolet travelled across the expanding “The light[section of the spectrum] that’s been redshifted that we’ll measure at our telescope will be light into that the nearwas originally mostly in the ultraviolet [section of to be able infrared,” explains Muzerolle. “You have the spectrum] that’s been redshifted into the nearto look at longer wavelengths in the near-infrared infrared,” explains Muzerolle. “You have to be able in order to detect galaxies] at all.” to [region] look at longer wavelengths in the[the near-infrared Like spectrographs, NIRSpec will break [region] in all order to detect [the galaxies] at all.” Like all the spectrographs, NIRSpecobjects will break down light of celestial into spectra > down the light of celestial objects into spectra >

EMISSION LINES

Þ NIRSpec’s flter carousel sits in the centre of the device and holds eight light flters Þ NIRSpec’s flter carousel sits in the centre of the device and holds eight light flters skyatnightmagazine.com 2014


76

76

Þ The JWST will see the

a spectrum, it will frst encounter the array. Here a Universe in infrared, panel of roughly a quarter of a million microscopic tell astronomers much about what they’re looking allowing it to look back doors, or ‘shutters’, can be programmed to remain at. But NIRSpec’s great strength will be its ability to at the earliest galaxies either open or closed while the instrument is carry out what is known as multi-object spectroscopy. making its observations. The result being that light “With a traditional spectrograph you have one slit will only be let through from a select few parts that, generally speaking, is only big enough to put a spectrum, it will frst encounter the array. Here a > whose features, such as dark absorption lines, can Þ The JWST will see the of theofinstrument’s feld of view – the parts that onto one object, like one star. You have to go one at Universe in infrared, panel of roughly a quarter a million microscopic tell astronomers much about what they’re looking time to build upstrength a largewill be its ability to allowing it to look back doors, or ‘shutters’, can be programmed to remain contain the objects the at.aBut NIRSpec’s great at the earliest galaxies either open or closed while the instrument is carry out what is known as multi-object spectroscopy. astronomers specifcally sample of spectroscopy of making its observations. The result being that light want spectra of. “With a traditional spectrograph you have one slit many different stars,” will only be let through from a select few parts that, generally speaking, is only big enough to put “For example if you explains Muzerolle. of the instrument’s feld of view – the parts that onto one object, like one star. You have to go one at want to take spectroscopy NIRSpec will be able to contain the objects the a time to build up a large astronomers specifcally of stars in a cluster you sample of spectroscopy of of capture the spectra want spectra of. many different stars,” celestial point the telescope at the around a hundred “For example if you explains Muzerolle. cluster and then open the shutters at the positions objects, such as stars or faint galaxies, in one shot. want to take spectroscopy NIRSpec will be able to of the starsinthat you’re It’s able to do this thanks to an advanced piece of of stars a cluster youinterested in,” explains capture the spectra of Muzerolle. of the rest of the shutters [would technology known point the“All telescope at the around a hundred celestialas a micro-shutter array. cluster and then open theclosed shuttersso at that the positions objects, such as stars or faint galaxies, in one shot. be] you don’t get any background or of the stars that you’re interested in,” explains light getting through.” It’s able to do this thanks to an advanced piece of other contaminating Muzerolle. “All of the rest of the shutters [would technology known as a micro-shutter array. The light going through the open shutters “Even on the ground there are not a lot of be] closed so that you don’t get any background or the chosen targets will then fall onto one of instruments that have used this kind of other contaminatingfrom light getting through.” Shut out the light NIRSpec’s gratings, technology,” says Muzerolle. In essence, the microThe light going through the open shutters which will produce spectra “Even on the ground there are not a lot of from the chosen targets then onto one instruments that have used this kind of thatwill can befall imaged byofthe instrument’s extremely shutter array’s role is to purposely block out large NIRSpec’s gratings, which will produce spectra technology,” says Muzerolle. In essence, the microsensitive camera chips. This image, of up to a parts of NIRSpec’s feld of view. Light from the that can be imaged by the instrument’s extremely shutter array’s role is to purposely block out large hundred tinyofinfrared JWST’s 6.5m mirror will be fed into NIRSpec via a sensitive camera chips. This image, up to a ‘rainbows’, will then be parts of NIRSpec’s feld of view. Light from the beamed back Earth complex systemwill of be optics. But beforeviait areaches the hundred tiny infrared ‘rainbows’, willtothen be where it can be analysed JWST’s 6.5m mirror fed into NIRSpec beamed back to Earth it can be analysed complex system of grating, optics. Butwhich before spreads it reaches the the light into bywhere astronomers on the ground. > instrument’s

“NIRSpec will be able to capture the spectra of around a hundred “NIRSpec will beobjects able to capture celestial in one shot” the spectra of around a hundred celestial objects in one shot”

eso/l. calçada, nasa/Jpl-caltech/ssi

nasa, thinkstock, nasa/esa, nasa/Jpl-caltech/malin space science systems, nasa, thinkstock, nasa/esa, nasa/Jpl-caltech/malin space eso/l. calçada, nasa/Jpl-caltech/ssi

science systems,

> whose features, such as dark absorption lines, can

Shut out the light

instrument’s grating, which spreads the light into



by astronomers on the ground. >

stellar spectroscopy april 77

insTrumenTs of discovery

a number of missions have used spectroscopy to deliver insights into the workings of the Universe

 ChemCam

insTrumenTs of discovery

NASA’s Curiosity rover certainly lives up to its original name – the Mars Science Laboratory. It is covered with cameras and scientifc instruments, including the ChemCam spectrometer. ChemCam works by zapping a target, such as an interesting rock, with a powerful laser. stellar spectroscopy april The plasma released is then analysed to 77 see what the target is made of. The range of the laser is such that the instrument can study features that are 7m away from the rover.

a number of missions have used spectroscopy to deliver insights into the workings of the Universe

 ChemCam NASA’s Curiosity rover certainly lives up to its original name – the Mars Science Laboratory. It is covered with cameras and scientifc instruments, including the ChemCam spectrometer. ChemCam works by zapping a target, such as an interesting rock, with a powerful laser. The plasma released is then analysed to see what the target is made of. The range of the laser is such that the instrument can study features that are 7m away from the rover.

 The Cosmic Origins Spectrograph The Cosmic Origins Spectrograph (COS) sits inside the Hubble Space Telescope. It was ftted to the orbiting observatory in 2009, when Hubble was visited by astronauts on Space Shuttle Atlantis. As its name suggests, the instrument is used to explore how various objects in the Universe, including galaxies and stars, came into being. In particular, COS has been used to examine the large-scale network of galaxies and gas present in space, known as the ‘cosmic web’.

 The Cosmic Origins Spectrograph

The Cosmic Origins Spectrograph (COS) sits inside the Hubble Space Telescope. It was ftted to the orbiting observatory in 2009, when Hubble was visited by astronauts on Space Shuttle Atlantis. As its name suggests, the instrument is used to explore how various objects in the Universe, including galaxies and stars, came into being. In particular, COS has been used to examine the large-scale network of galaxies and gas present in space, known as the ‘cosmic web’.

 VIMS The Cassini mission to Saturn has been exploring the ringed planet and its moons since 2004. On board the spacecraft are cameras, spectrometers and other scientifc instruments that have given us incredible insights into this remarkable planetary system. The Visible and Infrared Mapping Spectrometer (VIMS) has studied the icy jets coming from Saturn’s moon Enceladus, the hydrocarbon lakes on the  VIMS Titan weather in the gas giant’s atmosphere. The Cassini missionplanet’s to Saturn largest has beenmoon exploring theand ringed planet and its moons since 2004. On board the spacecraft are cameras, spectrometers and other scientifc instruments that have given us incredible insights into this remarkable planetary system. The Visible and Infrared Mapping Spectrometer (VIMS) has studied the icy jets coming from Saturn’s moon Enceladus, the hydrocarbon lakes on the planet’s largest moon Titan and weather in the gas giant’s atmosphere.

 HARPS The High Accuracy Radial Velocity Planet Searcher (HARPS) is

mounted HARPSon the ESO 3.6m Telescope at the La Silla Observatory TheinHigh Accuracy Velocity Planet site, Searcher is skies, HARPS is Chile. FromRadial this mountaintop with(HARPS) pristine mounted on hunt the ESO Telescope at thearound La Silla Observatory used to for3.6m planets orbiting distant stars. By looking in Chile. From this mountaintop site, with pristine skies, HARPS is for tell-tale movements of the lines in the spectra of these faraway used to hunt for planets orbiting around distant stars. By looking are to in use instrument to infer the presence forstars, tell-talescientists movements of able the lines thethe spectra of these faraway of extrasolar stars, scientists are worlds. able to use the instrument to infer the presence of extrasolar worlds.



78 stellar spectroscopy april

78 stellar spectroscopy april

> In capturing spectra of many stars at once,

the furthest reaches of the observable Universe,” Þ MIRI will be used to see what’s inside the dust says Sarah Kendrew, one of the astronomers who NIRSpec will allow astronomers to gather large clouds around newly worked on MIRI. “It is particularly sensitive to samples of data that should shine a light on the formed stars colder, dustier environments, the sort that we processes at work in star and planet formation. currently struggle to observe with the Hubble Space “From a statistical standpoint, this will really Telescope. Discs of dust around newly formed stars, advance the feld by a considerable amount,” says fortheexample, be excellent targets for MIRI. As Muzerolle. Whenofthe instrument surveys the most > In the furthest reaches of observablewill Universe,” capturing spectra many stars at once, Þ MIRI will be used to those are the birthplaces distant realms of the Universe it should also tell us see what’s inside the dust says Sarah Kendrew, one of the astronomers who of planets, that’s a NIRSpec will allow astronomers to gather large clouds around newly worked on MIRI. “Itparticularly is particularly exciting sensitive toarea of research.” samples data that should a light on galaxies the moreofabout how someshine of the frst were born formed stars colder, dustier environments, the sort that we processes at work star and planet formation. Spectrographs have and how theyinevolved. currently struggle to observe with the Hubble Space “From a statistical standpoint, this will really been at the very heart In doing so it will give Telescope. Discs of dust around newly formed stars, advance the feld by a considerable amount,” says astronomers a glimpse for example, will be excellent targets for MIRI. As of astronomy for two Muzerolle. When the instrument surveys the most centuries. And one can of the Universe as it wasit should also tell us those are the birthplaces of planets, that’s a distant realms of the Universe particularly exciting area of research.” more about how some of the frst galaxies were born only imagine the awe “a few hundred million Spectrographs have and how they with which Fraunhofer years afterevolved. the Big Bang”, been at the very heart In doing so it will give might regard modern says Muzerolle. “We of astronomy for two astronomers a glimpse hope that we’ll be able centuries. And one can instruments, like MIRI of the Universe as it was only imagine the awe “a to fewsee hundred and NIRSpec, if he could manymillion galaxies with which Fraunhofer see them in their clean years after that arethe inBig theBang”, process regard modern says Muzerolle. “We roommight today. Two hundred years ago his pioneering of forming, of collecting their initial material,” he instruments, like MIRI hope that we’ll be able work revolutionised understanding of the adds. NIRSpec isn’t the only spectrograph that will and NIRSpec, if heour could to see many galaxies Universe. Now the legacy beare operating on James Webb though. see them in their clean of that work is preparing that in the process room today. Two hundred years ago pioneering of forming, of collecting their initial material,” he to launch intohisspace to start a new, and equally work revolutionised ground-breaking, our understanding of the adds. NIRSpec isn’t the only spectrograph that will revolution of its own. S Universe. Now the legacy of that work is preparing be operating on James Webb though. MIRI, the Mid-Infrared Instrument, will study to launch into space to start a new, and equally of thepair objects NIRSpec will. But ground-breaking, revolution of its own. S Amany second ofthat eyes ABOUT THE WRITER because it observesInstrument, in the longer wavelength, MIRI, the Mid-Infrared will study Will Gater is an astronomy writer many of the objectsregion that NIRSpec But mid-infrared of thewill. electromagnetic ABOUT THE WRITER and journalist. the author of several because it observes in the longer wavelength, spectrum it will also be able to examine some Will Gater is an astronomy astronomy writer mid-infrared region of the electromagnetic books, he regularly phenomena thatbeNIRSpec can’t.some “With MIRI and journalist. the author of several spectrum it will also able to examine appears tV and radio. Find him astronomy books, he regularly we’ll be that ableNIRSpec to studycan’t. a whole phenomena “Withrange MIRI of astronomical appears tV and radio. Findon himtwitter: @willgater we’ll be ablefrom to study a whole astronomical objects inside ourrange ownofSolar System to on twitter: @willgater

“MIRI will be able to study a range of objects from inside our own Solar System to the “MIRI will be able to study a furthest range ofreaches objects from inside our of the Universe”

own Solar System to the furthest reaches of the Universe”

alamy

alamy

A second pair of eyes

objects from inside our own Solar System to



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mosaicing

THE MOON mosaicing

Pete Lawrence reveals his secrets to creating a frst-class lunar mosaic – from capturing the raw data to completion

THET MOON

known as ‘mosaicing’. This is the process of taking he Moon is a fascinating object to a number of zoomed-in shots and joining them both observe and image. The evertogether. The ultimate goal is to produce a highchanging shadows crossing the resolution image of the whole lunar disc. Over lunar surface make each and every the next few pages, we take you through all the Moon session unique and interesting. steps necessary to produce one from scratch. At roughly 0.5º across, it is relatively easy to photograph the entire lunar disc in one go with a DSLR camera, but this won’t bring out any ABOUT THE WRITER intricate A telescope ftted with a high known as ‘mosaicing’. This is the process of taking he Moondetail. is a fascinating object to Pete Lawrence is an number of zoomed-in shots and joining them both observe and image. Theyou ever-to get acloser, frame rate camera allows together. The ultimate goal is to produce a highchanging shadows crossing the expert imager. Each especially at high magnifcation. This typically resolution image of the whole lunar disc. Over lunar surface make each and every month, he tells us about results in an image that shows morethe detail but next few pages, we take you through all the Moon session unique and interesting. a new lunar target in our covers smaller of the Moon. steps necessary to produce one from scratch. At roughly 0.5aº across, it isarea relatively easy to Moonwatch column – fnd photographIfthe entire lunar disc indetailed one go with you want highly images of the it in the Sky Guide. a DSLR camera, but this won’t bring out any entire lunar disc, you need to use a technique ABOUT THE WRITER

Pete Lawrence reveals his secrets to creating a frst-class lunar mosaic – from capturing the raw data to completion

T

intricate detail. A telescope ftted with a high frame rate camera allows you to get closer, especially at high magnifcation. This typically results in an image that shows more detail but covers a smaller area of the Moon. If you want highly detailed images of the entire lunar disc, you need to use a technique

Pete Lawrence is an expert imager. Each month, he tells us about a new lunar target in our Moonwatch column – fnd it in the Sky Guide.

If you’re inspired by Pete’s effort, or think you could do the better, why not enter 2014’s Astronomy Photographer of the Year competition? Among the seven categories and prizes being If you’re inspired by Pete’s effort, or think you could the better, contested is ‘Our Solar System’, fordo which the judges are looking why not enter 2014’s Astronomy thecosmic Year backyard. For full for images that showPhotographer the best of ofour competition? Among the seven categories and prizes being details on how to sign up, the rules and how to submit your images, contested is ‘Our Solar System’, for which the judges are looking visit competition website. www.rmg.co.uk/astrophoto for images thatthe show the best of our cosmic backyard. For full details on how to sign up, the rules and how to submit your images, visit the competition website. www.rmg.co.uk/astrophoto

up of a staggering 213 panes

PEtE LawrEncE

PEtE LawrEncE

The author’s own mosaic of the waxing The author’s own mosaic of the gibbous Moon; it is made up of a staggering 213 panes waxing gibbous Moon; it is made

Use features at the leading edge of the frame as a guide for the next frame

Start

Use the features at the bottom of the frst row of frames as a guide for lining up the next row

Use features at the leading edge of the frame as a guide for the next frame

Start

Use the features at the bottom of the frst row of frames as a guide for lining up the next row

þ High frame rate

cameras are the best choice for lunar mosaicing

þ High frame rate

overlap

11

overlap

Area of Moon visible (pane)

Finish

cameras are the best choice for lunar mosaicing

overlap

overlap

Area of Moon Finish Þ Follow the surface horizontally; higher magnifcation increases the number of panes but the method stays the same visible (pane)

caPTURing THE MOON

Þ Follow the surface horizontally; higher magnifcation increases the number of panes but the method stays the same

caPTURing THE MOON

Before you can create a mosaic, you the magnifcation you use, for instance, the in right ascension and rotating the camera need detailed pictures. a mono high frame easier it is to get lost and miss a bit out; this so that features move parallel to the bottom Remembering few tool simple rules will help you to capture a lunar mosaic without gaps edge of the frame. finally, focus your setup. rate camera is really thea best for the job, is a common frustration when starting out. any allowing tocreate record a shortyou video of It pays to be termsinof image scale.and rotating the camera right ascension Before youyou can a mosaic, theeach magnifcation you use, forrealistic instance,inthe that features to the bottom need detailed pictures.ofathe mono highsurface) frame easier getyou’re lost andexperimenting miss a bit out; thiswithsomosaics ‘pane’ (segment lunar as anit is to If formove parallel An equatorial setup edge of the frame. finally, focus your useful setup. rate camera is really the best tool for the job, is a common frustration when starting out. is the most aVI fle, the individual frames of which can the frst time, capture a small number of allowing you to record a short video of each It pays to be realistic in terms of image scale. mount for mosaicing be stacked into a still image later. If your panes to start with so you can get a feel of ‘pane’ (segment of the lunar surface) as an If you’re experimenting with mosaics for An equatorial setup camera have anofinfrared-blocking Image scale betheadjusted most useful aVI fle, the doesn’t individual frames which can the frst time,what’s capturewhat. a small number of can is mount for mosaicing flter built-in, consider attaching an infraredusing optical amplifers such as Barlow be stacked into a still image later. If your panes to start with so you can get a feel of camera doesn’t have an infrared-blocking what’s what. Image scale can be adjusted pass flter. Doing so can reduce the effects lenses, but aim to keep your scope’s overall flter built-in, consider attaching an infraredusing optical amplifers such as Barlow of poor seeing. alternatively, try a red flter. focal ratio somewhere between f/15 and f/45. pass flter. Doing so can reduce the effects lenses, but aim to keep your scope’s overall Moving across the lunar surface only gobetween higherf/15 if the of poor seeing. alternatively, try a red flter. infocal ratio somewhere andseeing f/45. gets really good. overlapping issurface something that sounds driven, equatorially Moving across panels the lunar in only go higher ifathe seeing gets really good.mounted scope is overlapping panels something sounds a driven, equatorially mounted scope is easy to do, butis there are that pitfalls. The higher ideal. check camera alignment by slewing

PEtE LawrEncE x 4, stEvE marsh

PEtE LawrEncE x 4, stEvE marsh

Remembering a few simple rules will help you to capture a lunar mosaic without any gaps

easy to do, but there are pitfalls. The higher



ideal. check camera alignment by slewing

making a lunar mosaic april 83

Single pane at f/15

lunar mosaic april 83 Þ Lining up your panes with a generous overlap will lessen the chancesmaking of missing aapiece

Single pane at f/45

point your scope at the brightest part of There are various ways to move across Single pane at f/15 the Moon and adjust the camera’s gain and the Moon, but imaging in horizontal exposure so peak saturation is around 90 strips with lots of overlap is best. a good per cent. you should be able to leave this overlap is typically 20-25 per cent. When alone. of course, you can adjust the exposure lining up your frst pane, make a note of levels for each frame if you want, but this features close to the corners of the frame is more time consuming and requires and use these as guides when positioning greater effort when it comes to stitching for the next one. together; It’supgood practice image overlap the strips in the your Þ Lining your panes with to a generous will lessen chancespanes of missing a piece the advantage is less pane at f/45 Þ You’ll need fewer panes to complete your noise in dark regions and extraSingle navigational the same direction, moving back to the mosaic at f/15, but at f/45 you’ll get more detail point your scope at the brightest part of There are various ways to move across detail when crossing seemingly featureless same starting side of the Moon between the Moon and adjust the camera’s gain and the Moon, but imaging in horizontal long runs. Two fnal tips: mosaic captures areassaturation such as isthe lunar90seas. strips. features the frst strip ofexposure panes so peak around strips withuse lots of overlap in is best. a good typically take up lots of computer hard Whatbeyou need to make sure your adjustment per cent. you should ablewill to leave thisto do during a long overlap is typically 20-25 vertical per cent. When alone. you can adjust exposure often. This is lining upplenty your frst makeaa note of sketch disk space, so make sure you have plenty mosaicing run the is refocus gives ofpane, overlap. rough of of course, levels for each frame if you want, but this features close to the corners of the frame free; and plan ahead to make sure the essential to prevent defocusing caused by the feature in each frame can help. If you is more time consuming and requires and use these as guides when positioning Moon doesn’t disappear behind by a temperature variations. a 12V camping lose track, wind back to the last place you greater effort when it comes to stitching for the next one. neighbouring tree or rooftop part-way hairdryer also invaluable for removing know defnitely imaged. yourtopanes together; the is advantage is less It’s goodyou practice to image the stripsIt’s in better Þ You’ll need fewer panes to complete your your imaging session. moisture from dewed-up optics during thanback a gap! noise in dark regions and extra navigational mosaic at f/15, but at f/45through therisk sameduplication direction, moving to the you’ll get more detail

2 2

same starting side of the Moon between strips. use features in the frst strip of panes to make sure your vertical adjustment gives plenty of overlap. a rough sketch of the feature in each frame can help. If you lose track, wind back to the last place you know you defnitely imaged. It’s better to risk duplication than a gap!

detail when crossing seemingly featureless areas such as the lunar seas. What you will need to do during a long mosaicing run is refocus often. This is essential to prevent defocusing caused by temperature variations. a 12V camping hairdryer is also invaluable for removing moisture from dewed-up optics during

long runs. Two fnal tips: mosaic captures typically take up lots of computer hard disk space, so make sure you have plenty free; and plan ahead to make sure the Moon doesn’t disappear behind by a neighbouring tree or rooftop part-way through your imaging session.

PRocessing THE MOON Now that you’ve captured your panes as movie fles it’s time to turn them into high-resolution images

PRocessing THE MOON

‘stacked’ (averaged) to produce The nexT sTep is to process each aVI a fnal image. fle to produce one still image, ready The higher the quality for assembly into the fnal mosaic. threshold, the fewer frames for a large mosaic containing many Now that you’ve captured your panes as movie fles it’s time to turn them into high-resolution images will ultimately go into the individual panes this can be a daunting stack. This will result in the and tedious but there to produce The nexT sTeptask, is to process eachare aVIways ‘stacked’ (averaged) a fnal image. fleto tospeed produce one still image, ready sharpest output, but with less things up. The higher the quality for assembly into the fnal mosaic. frames to average, noise is The frst processing step is to analyse, threshold, the fewer frames for a large mosaic containing many more noticeable. set the quality register and stack the frames in eachwill ultimately go into the individual panes this can be a daunting threshold lower and there will aVI fle. There are various good (not to stack. This will result in the and tedious task, but there are ways sharpest output, but with less to average, to mention, speed thingsfree) up. computer programs that be more frames frames to average, noisein is a smoother, less The stepautomatically, is to analyse, resulting canfrst do processing this for you among set the quality register and stack the frames in each noisy result. however, using them registax, autostakkert! and more noticeable. threshold lower and there will aVI fle. There are various good (not to lower quality frames reduces avistack. for this project we’ll be using be more frames to average, mention, free) computer programs that image take care of theamong bulk of the resulting in aoverall smoother, less sharpness. canavistack do this fortoyou automatically, usingidea to perform them registax, autostakkert! and It’s a good processing and registax to perform noisy result. however, reduces avistack. this project we’ll be using number of test runs using waveletforsharpening on the results. lower qualityaframes overall image sharpness. avistack to take care of the bulk of the avistack if you’re not familiar The analysis step determines the It’s a good idea to perform processing and registax to perform theusing program. There are a quality of eachonstill Þ Quality analysis determines which frames test runs wavelet sharpening the frame results. and then a number of with will give you the best results for each pane lot of parameters and settings ranks them in order of how good they avistack if you’re not familiar The analysis step determines the with the program. There are a quality of each still frame and then Quality analysis determines which frames that can be confgured; theseÞ are are. a user-set quality threshold then will give you the best results for each pane lot of parameters and settings ranks them in order of how good they shown in a separate window and can determines how many of the frames up a control window allowing you to that can be confgured; these are are. a user-set quality threshold then be viewed by expanding the tree list. are used. The frames that are above adjust the settings for that section. you shown in a separate window and can determines how many of the frames up a control window allowing you to clicking threshold are ‘registered’ cansection. toggle you between automatic and be viewed byDouble expanding the tree on list.a parameter arethe used. The frames that are above (aligned) adjustsection, the settings for that Double clicking a parameter section, thetothreshold are ‘registered’ canwill toggle between automatic and for on example ‘frame selection’, bring one another. These (aligned) are then manual processing by clicking on > to one another. These are then

for example ‘frame selection’, will bring

manual processing by clicking on >



84

blurred, so to address this we’ll apply the useful if you’re not initially sure what excellent wavelet sharpening function you’re doing. within registax. avistack has a great batch-processing sharpening lunar images is something mode that can work on large numbers that needs to be done with great care. of aVI fles unattended. The end result once you start to apply sharpening to an is a single distilled image for each aVI image, it’s easy to get carried away and capture. Various output formats are push it just that little bit too far. available but we recommend pnG as If in doubt, it’s a good idea to leave this is a lossless format that many 84 the image up on your computer screen editing programs and fle viewers can Þ AVIs can be batch processed manually and walk away from it for a while. When easily display. other lossless fles can also or automatically you come back, your initial reaction be used, but how easy they are to view blurred, so to address this we’ll apply the useful if you’re not initially sure what will be a good indicator as to whether and manipulate may vary. avoid lossy excellent wavelet sharpening function you’re doing. you’ve taken things too far. If you’re > the gear wheel icon below the formats as JpeG. within registax. avistack has a great such batch-processing creating your mosaic at low magnifcation, following step-by-step guide below, section header. setting the toggle mode that can work sharpening lunar images is something on largethe numbers that needs to be done with great care. of aVI fles unattended. The end result a gentle tweak on the frst slider is all that’s the initial process delivers results with to ‘automatic processing’ lets avistack oncewill you start sharpeningrequired. to an image for each no sharpening. ToaVI the eye these lookto applynormally make decisions for you, which can beis a single distilled capture. Various output formats are available but we recommend pnG as this is a lossless format that many editing programs and fle viewers can easily display. other lossless fles can also be used, but how easy they are to view and manipulate may vary. avoid lossy formats such as JpeG. Click on ‘Process following the step-by-step guide below, fle’. When ‘Save the initial process deliversthe results with stacked image’ no sharpening. To the eye these will look

image, it’s easy to get carried away and push it just that little bit too far. If in doubt, it’s a good idea to leave the image up on your computer screen and walk away from it for a while. When you come back, your initial reaction will be a good indicatorAdd as toMovies whether you’ve taken things too(fle far.open) If you’re creating your mosaic at low magnifcation, a gentle tweak on the frst slider is all that’s normally required.

prOcEssiNg – sTEp by sTEp

STEP 1

Þ AVIs can be batch processed manually or automatically

> the gear wheel icon below the

STEP 2

Load a single AVI section header. setting the toggle AviStack for to into ‘automatic processing’ lets avistack processing. If make decisions for you, which can be you’re technically window appears minded, choose – see right – select ‘Settings’, PNG as the fle type Batch ‘Processing’, ‘All and defne the save processing manual’ from the folder. Make sure Add Movies main window ‘Save parameters’ is (fle open) Load a single AVI select Click on ‘Process menu. If not, ticked before you into AviStack for fle’. When the ‘Save ‘All automatic’. click on ‘Save’. Press processing. If stacked image’ Expand the ‘Save ‘Cancel’ when the That’s your frst processed fle complete. The you’re technically window appears stacked image’ ‘Post processing’ minded, choose – see right – select settings for this fle will be automatically used ‘Settings’, PNG as the fle type section and make window appears. for the batch processing run. Click ‘Add movies’ Batch ‘Processing’, ‘All and defne theTest savethe suitability of sure ‘Manual processing and select all of the fles to be processed, then manual’ from the folder. Make sure processing’ is set; click on “Automatic the result for wavelet click ‘Open’. Finally, click ‘Batch processing’ main window ‘Save parameters’ is processing” – see and let the program run through each fle in menu. If not, selectif shown. Expand ‘Post processing’ ticked before sharpening you select ‘Manual processing’. The fourclick on ‘Save’.step 5. If it is not, ‘Alland automatic’. Press turn, saving the results according to the settings Expand the ‘Save the That’s your frst processedyou fle chose complete. options below this should be deselected,‘Cancel’ whenrepeat and adjust parameter settings during in The the save stacked image box in stacked image’ ‘Post processing’ settingsto forassist. this fle will be automatically used as shown above. a manual run using the help options the previous step. section and make window appears.

prOcEssiNg – sTEp by sTEp

STEP 1

STEP 2

STEP 3

STEP 3

sure ‘Manual processing’ is set; click on “Automatic processing” if shown. Expand ‘Post processing’ and select ‘Manual processing’. The four options below this should be deselected, as shown above.

STEP 4

for the batch processing run. Click ‘Add movies’ and select all of the fles to be processed, then click ‘Open’. Finally, click ‘Batch processing’ and let the program run through each fle in turn, saving the results according to the settings you chose in the save stacked image box in the previous step.

STEP 5

STEP 6

Run RegiStax and click ‘Select’. Change ‘Files Wavelet sharpen all of the images, saving Once you have all the AviStack-processed of type’ to match the format of the processed each when done. Next, load the frst image PNG results, copy them all to a new folder, images (in our example, PNG). Load the frst into a layer-based editing program such as named something like ‘Wavelet-sharpened’. Run RegiStax and click ‘Select’. Change ‘Files Wavelet sharpen all of the images, saving Once you have all the AviStack-processed image. Withofthe Photoshop or GIMP and crop off any unwanted These arecopy the them fles all we’ll RegiStax; of leaving type’ to match the format the Wavelet processed tab selected, each whenclick done. Next, load the frst image PNG results, to aedit newin folder, example, PNG). Load the frst into aoflayer-based editingedge program such as Estimate and adjust the canvas the preview buttons to the right the sliders artefacts. named something untouched like ‘Wavelet-sharpened’. the originals means you can images rework(in ouron image. Wavelet tab details selected,will clickchange. Photoshop These areat theafles we’ll edit in RegiStax; leaving to see which Use theor GIMP and crop size off soany thatunwanted it will hold all of the panes; don’t them later date – say if new software or With the on the preview buttons to the right of the sliders edge artefacts. Estimate and adjust the canvas the originals untouched means you can rework slider that shows the fnest detail that isn’t worry too much if you get the size wrong as it more advanced techniques become available. to see which details will change. Use the size so that it will hold all of the panes; don’t them at a later date – say if new software or justthe noise Adjust to sharpen Select a black background Once you have your become fnal results, the originals slider that shows fnestgrain. detail that isn’t the slider worry too much if you getcan the be sizeadjusted wrong as later. it more advanced techniques available. theAdjust image taste. forathe new canvas area before you do this. canyou behave discarded you need the disk space. just noise grain. the to slider to sharpen can be adjusted later. Select black background Once your fnalifresults, the originals

STEP 5

STEP 6

the image to taste.

for the new canvas area before you do this.

PEtE LawrEncE x 10

STEP 4 PEtE LawrEncE x 10

Test the suitability of the result for wavelet sharpening – see step 5. If it is not, repeat and adjust parameter settings during a manual run using the help options to assist.

can be discarded if you need the disk space.



3

making a lunar mosaic april 85

sTiTching THE MOON

All the hard work you’ve put in up to this point is about to pay off with the best part, assembling the mosaic

The excITInG parT of mosaicing is Whether a full disc or a building the fnal image. There are free crescent, a lunar mosaic is programs that can do this automatically, one of the most rewarding making a lunar mosaic april 85 images you can produce including Microsoft’s excellent Image composite editor (Ice). Building the mosaic manually is a more time-consuming process, but ultimately a rewarding experience. Doing it yourself can also help to avoid the errors that sometimes occur usingwork automated Allwhen the hard you’veprograms. put in up to this point is about to pay off with the best part, assembling the mosaic If you followed our step-by-step guide The excITInG parT of mosaicing is Whether a full disc or a on the previous page, your base image building the fnal image. There are free crescent, a lunar mosaic is will contain a single fnished pane and programs that can do this automatically, one of the most rewarding your canvas willexcellent be of suffcient size to including Microsoft’s Image images you can produce composite take theeditor rest. (Ice). Building the mosaic manually is a more time-consuming Load the next frame in the sequence process, but ultimately a rewarding and draw a selection experience. Doing it yourselfbox can slightly also help smaller theerrors frame edge withinoccur it. apply a to than avoid the that sometimes when using automated 5-10 pixel featherprograms. to the selection. If you followed our step-by-step guide it into copy the selection and paste on the previous page, your base image the base image. use the arrow keys to will contain a single fnished pane and nudge the alignment your canvas willpane be ofinto suffcient size to with the take thelower rest. image. Toggling the visibility Load thenudged next frame in the of the layer onsequence and off will help and draw a selection box slightly smaller you to line it up accurately. than the frame edge within it. apply a small variations in tone between the 5-10 pixel feather to the selection. pasted baseand images can copy theand selection paste it intonormally be with by tweaking thedealt base image. usegently the arrow keys to the curves nudge paneshould into alignment toolthe – you apply with the adjustment the lower image. Toggling the visibility to the centre of the curve. for larger of the nudged layer on and off will help variations, or drop the brightness you to line it up raise accurately. of the image frst to between get it closer small variations in tone the to where

3

sTiTching THE MOON

pasted and base images can normally be dealt with by gently tweaking the curves tool – you should apply the adjustment to the centre of the curve. for larger variations, raise or drop the brightness of the image frst to get it closer to where

similar stage as before, save as ‘mosaic-002’ you want it, then use the curves tool to and fatten. repeat until the whole mosaic carry out fne adjustments. Þ Align your panes by zooming in and is complete. This technique means you The feathered edges of the pasted nudging them into place with the arrow keys back and address any major image should anysimilar straight stage as before,can save go as ‘mosaic-002’ you want it, then usepane the curves toolmake to and fatten. repeat until the wholefound mosaic at the end. carry out fneedges adjustments. problems hard to see. If some are still obvious, Þ Align your panes by zooming in and is complete. This technique means you The feathered edges of the pasted nudging them into place with the arrow keys When done, fatten the image and save set the eraser tool to 10 per cent strength can go back and address any major image pane should make any straight to a fle name of your choice. a gentle and gently rub it over any visible joins; problems found at the end. edges hard to see. If some are still obvious, tweak ofand brightness or contrast, or a small them. When done, fatten the image save set the eraserthis toolshould to 10 perhide cent strength adjustment using the Levels and curves for very large mosaics that stretch to a fle name of your choice. a gentle and gently rub it over any visible joins; tweak of brightness or contrast, or a small this should hide them. tools, can help to fnish off your masterpiece. your computer’s memory, assemble a adjustment using the Levels and curves for very large mosaics that stretch It takes a bit of work to build such a mosaic batch of panes and then save the layered tools, can help to fnish off your masterpiece. your computer’s memory, assemble a once it’s done, the feeling of image to asave flethe called ‘mosaic-001’. It takes aflatten bit of work tomanually build such abut mosaic batch of panes and then layered will the image and continue withbut the manually once it’s satisfaction done, the feeling of be immense; that is unless image to a fle called ‘mosaic-001’. flatten loading Þ You may need to adjust brightness and satisfaction will be immense; that is unless the image and continue loading with the you’ve missed a bit of course! S next set of frames. When you get to a contrast to blend adjacent panes together Þ You may need to adjust brightness and contrast to blend adjacent panes together

next set of frames. When you get to a

you’ve missed a bit of course! S




UK

Retailer Guide


UK

Find the right one for you: buy your telescope from a specialist retailer

Retailer Guide I

t is quite easy to become daunted by the vast array of equipment that is available to today’s amateur astronomers. Different makes, different models, different sizes and optical arrangements – if you’re new to the hobby, how do you make sense of all these details and fnd the telescope that will show you the Universe? The answer lies in buying from a specialist retailer – somewhere that really knows what they’re talking about. Like quite easy become daunted by have the vast array thet isretailers intothis guide, they’ll the practical knowledge of equipment that is available to today’s amateur that will guide you towards the scope that won’t end up astronomers. Different makes, different models, different gathering dust in a cupboard. sizes and optical arrangements – if you’re new to the Today there are over models ofand telescope hobby, how do you make sense1,000 of all these details fnd the to choose telescope that will showand yourefectors, the Universe? from – refractors Dobsonians and Newtonians, The answer lies Maksutov-Cassegrains. in buying from a specialist retailer Schmidtand And –just as important as somewhere that really knows what they’re talking about. Like the telescope is the mount it sits on; but do you go for equatorial the retailers in this guide, they’ll have the practical knowledge orwill altazimuth, manualthe orscope Go-To? about accessories that guide you towards thatAnd won’twhat end up like eyepieces and fnderscopes? gathering dust in a cupboard. Today there are over 1,000 models of telescope to making choose a decision, That’s certainly a lot to consider before from – refractors and refectors, Dobsonians and Newtonians, but a specialist retailer will help you make that decision, taking Schmidt- and Maksutov-Cassegrains. And just as important as important considerations like portability, construction and price the telescope is the mount it sits on; but do you go for equatorial account. orinto altazimuth, manual or Go-To? And what about accessories So if youand need friendly, face-to-face advice and excellent like eyepieces fnderscopes? That’s certainly a lot consider making a decision, aftersales service,tofree frombefore biased opinions, specialist but a specialist retailer will help you make that decision, taking telescope retailers are the place to go for a helping hand important considerations like portability, construction and price through into account.the technical literature and tables of fgures. They’ll help youneed fndfriendly, a scope that combines quality and convenience at So if you face-to-face advice and excellent aftersales free from biased opinions, specialist a priceservice, that’s right.

Find the right one for you: buy your telescope from a specialist retailer

I

telescope retailers are the place to go for a helping hand through the technical literature and tables of fgures. They’ll help you fnd a scope that combines quality and convenience at a price that’s right.


TRinG AsTRonomy cenTRe

Telescope House Founded in 1785, Telescope House has been responsible for supplying many well-known Astronomers with telescopes and equipment. The late Sir Patrick Moore bought the majority of his telescopes from the company, including his very frst instrument. With a friendly showroom in Surrey, a number one ranked retail website and a service centre with fully qualifed staff, the company offers equipment from manufacturers such as Meade, Revelation, Coronado, Bresser, Skywatcher, Orion USA, TeleVue, Vixen and Explore Scientifc. Telescope House Founded in 1785, Telescope Whether it’s advice onHouse your has frst telescope, been responsible for supplyingAstrophotography many to setting up advanced well-known Astronomers with telescopes systems, the staff at Telescope House have a and equipment. The late Sir Patrick Moore wealth experience and instant access to bought the of majority of his telescopes the right stock to back it up. from the company, including his very frst instrument. With a friendly showroom in Surrey, a number one ranked retail website and a service centre with fully qualifed staff, the company offers equipment from manufacturers such as Meade, Revelation, Coronado, Bresser, Skywatcher, Orion USA, TeleVue, Vixen and Explore Scientifc. Whether it’s advice on your frst telescope, to Established setting up advanced Astrophotography for over 60 years, systems, the staff at Telescope House have a we at Sherwoods are one of the wealth of experience and instant access to suppliers of theMidlands right stock toleading back it up.

At Tring Astronomy Centre we know that choosing the right equipment can be a minefeld, but we strongly believe that seeing telescopes in the fesh and talking to an expert in a relaxed environment ADVERTISEMENT can really help. That’s why we have FEATURE a coffee machine, a fully stocked bicuit barrel, and 45+ telescopes on display. As well as representing leading brands such as Celestron, Sky-Watcher, Baader Planetarium, Altair Astro, Vixen, TRinG AsTRonomy Opticron, AstroTrac, iOptron, Lunt, cenTRe Starlight Instruments, ZW Optical and At Tring Astronomy Centre know many we more wethat also offer a hire service choosing the right equipment can be a so you can even try before you buy! So minefeld, but we strongly believe that areand you waiting for? Visit or contact seeing telescopes inwhat the fesh talking Tring Astronomy Centre and to an expert in a relaxed environment 01342 837610 01442 822997 can really help. That’s why we have a lets talk Astronomy! www.telescopehouse.com www.tringastro.co.uk coffee machine, a fully stocked bicuit

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The Widescreen cenTre

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GReen wiTcH

suppliers of telescopes, binoculars and accessories for astronomy. Founded by former wiTcH members of the Royal GReen Greenwich Observatory in 1998, Green Witch is one of the UK’s leading GreenofWitch is dedicated helping suppliers telescopes, binoculars to and accessories for astronomy. Founded you choose and use the equipment that byisformer right members for you.of the Royal Greenwich Observatory in 1998, We also carry an toextensive Green Witch is dedicated helping range ofchoose telescopes and for nature you and use the binoculars equipment that is and right for you. which you are welcome to leisure, Webefore also carry anbuy. extensive range you visit try you Whether of telescopes and binoculars for nature our showrooms or buy online you can and leisure, which you are welcome to sureyou of buy. excellent service. trybe before Whether you visit our showrooms or buy online you can be sure of excellent service.

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88

Skills

Brush up on your astronomy prowess with our team of experts

Contents

88

The guide

How to

Sketching

Scope doctor

88

90

93

95

An introduction to the Milky Way’s neighbouring galaxies

Get steadier binocular views with a pair of stabilising techniques

Skills SKILLS

Contents The guide

88

An introduction to the Milky Way’s neighbouring galaxies

SKILLS With

Elizabeth Pearson

Discover how to sketch Mars, which reaches opposition this month

Brush up on your astronomy prowess with our team of experts

The guide How to

Sketching

Scope doctor

90

93

95

Get steadier binocular views with a pair of stabilising techniques

Discover how to sketch Mars, which reaches opposition this month

The Local Group

Steve Richards answers your astro equipment queries

Steve Richards answers your astro equipment queries

The Milky Way is one of the mainstays in this galactic family

The guide

With Elizabeth Pearson

The Local Group

Andromeda Galaxy, M31 The Milky Way is one of the mainstays in thisThegalactic family

The Milky Way

M33

The Triangulum Galaxy, M33

MARK GARLICK/SCIENCE PHOTO LIBRARY, THINKSTOCK x 3, NOAO/AURA/NSF

MARK GARLICK/SCIENCE PHOTO LIBRARY, THINKSTOCK x 3, NOAO/AURA/NSF

The Milky Way

The Andromeda Galaxy, M31 The Triangulum Galaxy,

The Local Group of galaxies only contains three spirals, our own Milky Way, M31 and M33 The Local Group of galaxies only contains three spirals, our own Way,Milky M31 and M33that Way make Milkythe

T T

they must be affected he Milky Way is not alone in Magellanic Clouds. Together, they by its gravitational pull. By that time it the Universe. Our Galaxy up the Local Group. the introduced Milky Way that they must be affected he Milky is not alone in spiral, Magellanic they make was already known that most galaxies and Way its neighbouring the Clouds. TheTogether, term ‘Local Group’ was by its gravitational pull. By that time it the Universe. Our Galaxy up the Local Group. are found in either groups or their larger Andromeda Galaxy, are locked by Edwin Hubble in 1936 while he was was already known that most galaxies and its neighbouring spiral, the The term ‘Local Group’ was introduced cousins, together by gravity. Caught along with measuring the distances to extragalactic are found in either groups or theirclusters, larger and so Hubble suggested Andromeda Galaxy, are locked by Edwin Hubble in 1936 while he was that these objects were all part of our them by aregravity. a hostCaught of 30-50 galaxies, objects. Hubble realised thatcousins, severalclusters, of theand so Hubble suggested together alongsmaller with measuring the distances to extragalactic that so these objects all part of our them are a host of 30-50 galaxies, and objects. realised of the were own group. among them M33 smaller in Triangulum the Hubble objects hethat hadseveral catalogued close to wereGalaxy’s among them M33 in Triangulum and the



objects he had catalogued were so close to

Galaxy’s own group.

skiLLs APRIL 89

Observing the LocaL Group A few objects in the Local Group are prime targets for observing and imaging. That said, the light from these galaxies is spread out and

diffuse, meaning they can be a challenge to fnd and picking out detail is very tricky. As with most deep-sky objects, it’s critical to

observe from a very dark site – from good locations you may be able to see some of these four with the naked eye.

skiLLs APRIL 89

Observing the LocaL Group A few objects in the Local Group are prime targets for observing and imaging. That said, the light from these galaxies is spread out and

diffuse, meaning they can be a challenge to fnd and picking out detail is very tricky. As with most deep-sky objects, it’s critical to

observe from a very dark site – from good locations you may be able to see some of these four with the naked eye.

ThE AndroMEdA GALAXY, M31

ThE MILKY WAY

Equipment: naked eye, binoculars, telescope Constellation: Andromeda At mag. +3.5, M31 is the brightest galaxy visible from the northern hemisphere; also look out for its satellite galaxies above and below it, designated M32 and M110 – you’ll need at least binoculars for these.

Equipment: naked eye The Milky Way appears as a band of stars across the sky as we look out through the plane of our Galaxy. The exact position of the band on the sky changes throughout the year, showing us different parts of the Galaxy.

ThE AndroMEdA GALAXY, M31

ThE MILKY WAY

Equipment: naked eye, binoculars, telescope Constellation: Andromeda At mag. +3.5, M31 is the brightest galaxy visible from the northern hemisphere; also look out for its satellite galaxies above and below it, designated M32 and M110 – you’ll need at least binoculars for these.

Equipment: naked eye The Milky Way appears as a band of stars across the sky as we look out through the plane of our Galaxy. The exact position of the band on the sky changes throughout the year, showing us different parts of the Galaxy.

ThE LArGE And SMALL MAGELLAnIC CLoudS (LMC And SMC)

ThE TrIAnGuLuM GALAXY, M33

Equipment: naked eye, binoculars, telescope Constellation: dorado/Mensa (LMC); Tucana (SMC) This duo are only visible from the southern hemisphere. The LMC is an irregular galaxy, though a strong bar-like structure near the centre suggests it may once have been a spiral; the SMC is an irregular dwarf.

Equipment: Binoculars, telescope Constellation: Triangulum In April, the mag. +5.7 Triangulum Galaxy will appear low on the horizon in the early hours of the morning. It is most easily spotted with binoculars due to its low surface brightness.

ThE LArGE And SMALL MAGELLAnIC CLoudS (LMC And SMC)

ThE TrIAnGuLuM GALAXY, M33

Equipment: naked eye, binoculars, telescope Equipment: Binoculars, telescope Constellation: dorado/Mensa (LMC); Tucana (SMC) Triangulum infuence.Constellation: Calculating distances on these Over the years astronomers have found about four billion years. While this will be This duo are only visible from the southern hemisphere. The LMC is an In April, the mag. +5.7 Triangulum Galaxy will appear low on the huge scales is extremely diffcult using the more nearby dwarf galaxies, upping the the most spectacular crash these two spirals irregular galaxy, though a strong bar-like structure near the centre horizon in the early hours of the morning. It is most easily spotted of resolving individual number inonce the have Local Group to the several suggests it may been a spiral; SMC isdozen. an irregularusual dwarf. techniques with binoculars due to its low surface brightness. have encountered, it won’t be the frst. The

stars visually and calculating redshift with remains of dwarf galaxies that have been The exact population is still a matter of spectroscopy. In on several a galaxy has years. some contention: in order to be part of the subsumed can be seen in infuence. Calculating distances these cases Over the years astronomers have found about four billion While this by willAndromeda be huge scales isatextremely diffcult to using more nearby dwarf galaxies, the most spectacular crash two spirals frst appeared be the part ofthethe Local group, a galaxy needs upping to be gravitationally ourthese galactic companion, while a structure usual techniques of resolving individual number in the Groupmembers, to several dozen. havedistance encountered, it won’t be the TheStellar Stream is believed Group, only for a more precise bound to Local the other something called thefrst. Virgo stars visually and calculating redshift with remains of dwarf galaxies that have been The exact population is still a matter of measurement to place it in a nearby group; to be what’s left of a dwarf that is currently that can be hard to work out. spectroscopy. In several cases a galaxy has some contention: in order to be part of the subsumed by Andromeda can be seen in thistohappened with irregularour galaxy merging with the Milky Way. When the at frst appeared be part of the Local group, a galaxy needs to be gravitationally galactic companion, while a structure 86. Oncedistance proposed tocalled be part of the Group, only UGCA for a more precise bound to the other members, something the Virgo Stellarlargest Stream members is believed of the Local Group merge, measurementLocal to place it in a nearby that can be work out. be what’s left of a dwarf is currently Group, recentgroup; studies to have placed theythat will form a massive elliptical galaxy. Most ofhard the to galaxies in the Local Group this happened with irregular galaxy merging with the Milky Way. When What willthe happen to the smaller are satellites of either the Milky Way or the it in the IC 342/Maffei Group, an adjacent UGCA 86. Once proposed to be part of the largest members of the Local Group merge, Gravitational grasp congregation of galaxies within 10 million galaxies is a little more uncertain. Some Andromeda Galaxy. There are a few Local Group, recent studies have placed they will form a massive elliptical galaxy. Most of the galaxies in the Local Group lightyearsGroup, of our get consumed in the merger, others that are not, such Way as the Aquarius it in the IC 342/Maffei an own. adjacent What will happen towill the smaller areothers satellites of either the Milky or the Telling which galaxies are part of the Local will continue and Phoenix Dwarf Galaxies, but we know congregation of galaxies within 10 million galaxies is a little more uncertain. Someto orbit as satellite galaxies Andromeda Galaxy. There are a few lightyears of our own. will get consumed in the merger, others others that are not, such as the Aquarius Group will be a lot easier in a few billion and some may be thrown out of the that they must be part of the group as they Telling which galaxies are part of the Local will continue to orbit as satellite galaxies and Phoenix Dwarf Galaxies, but we know years, however, as they are slowly being system entirely. S are too close not to be affected by the Group will be a lot easier in a few billion and some may be thrown out of the that they must be part of the group as they pulled together. The largest two members combined gravity of the two large spirals. years, however, as they are slowly being system entirely. S are too close not to be affected by the of the The gravity problem comes for galaxies aretogether. Elizabeth Pearson is BBC Sky at Night pulled Thegroup, largest Andromeda two members and the Milky Way, combined of the two large spirals. that of the group, are Andromeda andtowards the MilkyaWay, The problem galaxies gravitational that are Elizabeth Pearson Sky at Night Magazine’s staff writer heading massive collision in is BBC on the edgecomes of theforgroup’s

Gravitational grasp

on the edge of the group’s gravitational

are heading towards a massive collision in

Magazine’s staff writer



90

SKILLS

How to

Get steadier binocular views

90 With Stephen Tonkin

SKILLS

Two techniques to help you split tricky double stars in no time Even heavy binoculars can be held steady if your arms aren’t taking the weight

How to

Get steadier binocular views With Stephen Tonkin

Two techniques to help you split tricky double stars in no time Even heavy binoculars can be held steady if your arms aren’t taking the weight

T

he ‘grab and go’ nature of high altitudes. In order to improve things, and neck: as you lean further back to small or medium binoculars we need to apply some ergonomics. observe higher targets, more and more of makes them very attractive Let’s assume you hold your binoculars the weight of the binoculars rests on your astronomical instruments. as described previously. When looking head and less is borne by your arms, Soonerheor‘grab later, however, you will fnd that through them horizontally, all the weight making them and go’ nature of high altitudes. In order to improve things, and neck: as you lean further back to less liable to shake. And this small medium binoculars we need to apply someby ergonomics. higher targets,ismore you need toorsteady them a bit more in is borne your arms, which observe are cantilevered notand themore onlyofbeneft. makes them very attractive binoculars weight of the binoculars your order to make a critical observation. Let’s assume outyou in hold frontyour of you; the strain the is mostly taken As rests any on structural engineer will tell you, astronomical instruments. as described previously. When looking head and less is borne by your arms, One solution is to mount them, but a by the deltoid muscles in your shoulder. the triangle is the simplest and most stable Sooner or later, however, you will fnd that through them horizontally, all the weight making them less liable to shake. And this mount immediately compromises their As you observe higher targets, your you need to steady them a bit more in is borne by your arms, which are cantilevered is not the only beneft. mechanical structure. By holding your portability adds a layer of complexity. becomes more horizontal binoculars this position, you create two order to make a and critical observation. out in front offorearm you; the strain is mostly taken As anyand structural engineer will tellinyou, One is to mount but a viewsby the deltoidyour muscles in your shoulder. triangle is the simplest and most stable Yousolution can, however, getthem, steadier triceps take more of thethestrain. triangles with your arms – these triangles mount immediately compromises their As you observe higher targets, your mechanical structure. By holding your simply by changing the way you hold your Additionally, when you observe objects at share a common side comprised of your head portability and adds a layer of complexity. forearm becomes more horizontal and binoculars in this position, you create two binoculars, which is what we are going high altitude your arms are much higher and neck. The result is an immediately You can, however, get steadier views your triceps take more of the strain. triangles with your arms – these triangles to explain thisthe month. heart,objects reducing blood fow side comprised noticeable improvement in stability. This simply by changing way you hold your Additionally,than whenyour you observe at the share a common of your head Most of us instinctively hold Porroto your arm muscles. This means they are improvement is even more marked if you binoculars, which is what we are going high altitude your arms are much higher and neck. The result is an immediately to prism explain binoculars this month. by the prism housings than your heart, reducing the blood fow noticeable improvement in stability. This more likely to tire and start shaking. What take up a position where your head is also Most of us instinctively hold Porroto your arm muscles. This means they are improvement is even more marked if you and roof-prism binoculars about midway we need is a way of transferring the strain. supported, such as lying on a sunlounger. prism binoculars by the prism housings more likely to tire and start shaking. What take up a position where your head is also along their length. This is tolerable for One way to do this is called the If the binoculars have a suffciently long and roof-prism binoculars about midway we need is a way of transferring the strain. supported, such as lying on a sunlounger. terrestrial targets, can quickly become armthebrace’, in which you strap, we canlong steady the view even more by along their length. This isbut tolerable for One way to‘triangular do this is called If the binoculars have a suffciently terrestrial targets,you but can become ‘triangular arm brace’,some in which strap, we head can steady theusing view even more by tiring when are quickly observing objects at transfer of you the weight to your a second technique similar that used

all pictures: stephen tonkin

all pictures: stephen tonkin

T

tiring when you are observing objects at



transfer some of the weight to your head

using a second technique similar that used

SKILLS april 91

STEP-BY-STEP GUIDE

TOOLS AND MATERIALS if you need a new strap for the ‘rife sling’ method Finish

use a soldering iron to heat seal cut ends to prevent them fraying.

SKILLS april 91

Materials

approximately 1.7m of nylon webbing STEP-BY-STEP GUIDE TOOLS AND to suit the strap-lugs on your binoculars, which are usually about 8mm wide, and MATERIALS a pair of 3-bar slide buckles to ft the

if you need a new strap for you may be able to reuse the thewebbing; ‘rife sling’ method

ones on your existing strap.

Finish

usetools a soldering iron to heat seal cut ends to prevent them fraying.

scissors, craft knife or hot cutter, tape measure, ruler. Materials

STEP 1

To fnd the correct position for your hands, cup them and hold them to your face so that the top knuckle of your thumb rests securely in the indent of your eye socket; the lower bone of your thumb should rest comfortably on your cheekbone.

approximately 1.7m of nylon webbing to suit the strap-lugs on your binoculars, which are usually about 8mm wide, and marksmen tobuckles steadytoaftrife. abypair of 3-bar slide the For this webbing; you may be able to reuse the method. reason, we call it the ‘rife sling’ To fnd the correct position for your hands, ones on your existing strap.

STEP 1

It works by creating tension between your cup them and hold them to your face so that the top knuckle of your thumb rests arms and the binoculars; the tension reduces tools securely in the indent of your eye socket; scissors, craft of knife or binoculars hot cutter, tapeto shake. the lower bone of your thumb should rest the ability the measure, ruler.

comfortably on your cheekbone.

STEP 2

With the same cupped-hand position, hold the prism housings of the binoculars with your third and fourth fngers. Your forefnger will rest lightly on the eyepiece barrel and your middle fnger on the eyepiece bridge. Your palms will take the weight of the binoculars.

STEP 2

With the same cupped-hand position, hold the prism housings of the binoculars with your third and fourth fngers. Your forefnger will rest lightly on the eyepiece barrel and your middle fnger on the eyepiece bridge. Your palms will take the weight of the binoculars.

Armed and ready?

This technique can be slightly awkward

by marksmen to steady a rife. For this untilweyou used it, but get it right reason, callget it the ‘rifeto sling’ method. It works tension betweenThe yourrife sling and itbyiscreating quite comfortable. arms and the binoculars; the tension reduces method doesn’t quite have the stability of the ability of the binoculars to shake.

STEP 3

STEP 4

STEP 5

STEP 6

mounted binoculars, but it’s not a long way off for a pair 10x50s. You should certainly Raise the binoculars to your eyes and re-settle For the ultra-stable rife sling hold, you may Armed andofready? fnd that double stars that used to be tricky your thumbs into their original positions resting need a longer strap. Cut a 1.7m length of This technique can be slightly awkward until used to it, seem but getmuch it righteasier. on your cheekbones. If you have centre-focus nylon webbing and attach it to the strap to you splitgetsuddenly and itEven is quite The rife sling binoculars, use your middle or ring fnger to lugs of your binoculars. Secure the strap oncomfortable. larger binoculars that shouldn’t method doesn’t quite have the stability of adjust the focus wheel. If you have individual with the 3-bar buckles, with the free ends really be hand-held – 15x70s for example mounted binoculars, but it’s not a long way eyepiece focusing, use your STEP forefngers.4 trapped against the buckles. STEP 3 the difference rife sling off–for a pair of 10x50s.between You shouldthe certainly Raise the binoculars to your eyes and re-settle For the ultra-stable rife sling hold, you may approach and the normal of holding fnd that double stars that used to way be tricky your thumbs into their original positions resting need a longer strap. Cut a 1.7m length of on your cheekbones. If you have centre-focus nylon webbing and attach it to the strap to them split suddenly seem much easier. is quite marked. Not only will you binoculars, use your middle or ring fnger to lugs of your binoculars. Secure the strap Even on larger binoculars that shouldn’t fnd that more detail becomes visible in adjust the focus wheel. If you have individual with the 3-bar buckles, with the free ends really be hand-held – 15x70s for example eyepiece focusing, use your forefngers. trapped against the buckles. large ‘fuzzy blobs’ like the Orion Nebula – the difference between the rife sling and the Andromeda Galaxy, but also some approach and the normal way of holding them is quitewill marked. Not more only will you and seem clusters resolve easily fnd more detail becomes visible tothat have more stars. It can alsoinhelp large ‘fuzzy blobs’ like the Orion Nebula distinguish between stars and those very and the Andromeda Galaxy, but also some smallwill objects at low clusters resolvethat morelook easilystellar and seem as help active galaxy M77 to magnifcation, have more stars. Itsuch can also distinguish those very in Cetusbetween or the stars Ringand Nebula, M57, in Lyra. smallAn objects that look stellar at low added bonus to the improved magnifcation, such as active galaxy M77 stability is that holding your binoculars in Cetus or the Ring Nebula, M57, in Lyra. likeadded this bonus also has the advantage of An to the improved Hold the binoculars in front of you so the Raise the binoculars to your eyes as before considerably reducing arm fatigue, so your stability is that holding your binoculars strap is looped down and, one at a time, put and tension the strap by pushing your STEP 5 STEP 6 likebinocular this also has the advantage of observing sessions can become Hold the binoculars frontthrough of you so the the strap Raise the binoculars to your eyes as beforeYou should feel the binoculars your in arms and adjust its elbows apart. considerably reducing arm fatigue, so your longer and much more productive. S strap is loopedposition down and, time, putto just andabove tension your the strap by pushing pushing your soone thatatita comes down on your hands and the binocular observing sessions can become longer and much more productive. S

your arms through the strap and adjust its apart. You should feel the binoculars elbows. Hold the binocularselbows the same way whole ‘system’ of arms, position so that it comes to just above your pushing down on your hands and the Stephen Tonkin writes our Binocular elbows. tour Hold the as binoculars you did before. becoming very rigid. the same way whole ‘system’ of arms, head and straps Stephen ouritBinocular tourGuide each Tonkin monthwrites – fnd in the Sky as you did before. becoming very rigid.

head and straps

each month – fnd it in the Sky Guide



Black Holes Explained Taught by Professor Alex Filippenko UNIVERSITY OF CALIFORNIA, BERKELEY

O

E R BY 1 8 M

TIME O F

R FE

55%

O

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off

AY

LIM

off

E R BY 1 8 M

A General Introduction to Black Holes

2. The Violent Deaths of Massive Stars 3. Gamma-Ray Bursts—The Birth of Black Holes 4. Searching for Stellar-Mass Black Holes Monster of the Milky Way and Other Galaxies Black Holes5. Explained

6. Quasars—Feasting Supermassive Black Holes

AY

55%

RD

ED IT

1.

D TIME OF E IT

R FE

LIM

LECTURE TITLES

Taught by Professor Alex Filippenko UNIVERSITY OF CALIFORNIA, BERKELEY 7. Gravitational

LECTURE TITLES 8. 1.

Waves—Ripples in Space-Time

The Wildest Ride in the Universe

A General Introduction to Black Holes

9. Shortcuts through the Universe and Beyond?

2. The Violent Deaths of Massive Stars

10. Stephen Hawking and Black Hole Evaporation

3. Gamma-Ray Bursts—The Birth of Black Holes

11. BlackBlack Holes and 4. Searching for Stellar-Mass Holes

the Holographic Universe

5. Monster of the Milky Way and Otherand Galaxies 12. Black Holes the Large

Hadron Collider

6. Quasars—Feasting Supermassive Black Holes 7.

Gravitational Waves—Ripples in Space-Time

8. The Wildest Ride in the Universe 9. Shortcuts through the Universe and Beyond? 10. Stephen Hawking and Black Hole Evaporation 11. Black Holes and the Holographic Universe 12. Black Holes and the Large Hadron Collider

Make Sense of Black Holes Black Holes Explained

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Make Sense of Black Holes

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SKILLS APRIL 93

SKILLS

N

Sketching Mars

P

SKILLS APRIL 93

With Carol Lakomiak

SKILLS Need TO KNOW Name: Mars

N

Sketching North polar cap

Mars

coNSteLLatIoN: Virgo

Arabia

WithRa: Carol Lakomiak 13h 22m to 12h 43m

dec: –05° 51’ to –02° 57’

North polar cap Mare AcidaliumSinus

beSt tIme to SKetch: 1-30 April, 11pm-2am BST dec: –05° 51’ to –02° 57’ (10pm-1am UT)

Aeria

Moab

Meridiani Arabia

Virgo

Ra: 13h 22m to 12h 43m

N

Eden

Need TO KNOW

equIpmeNt: 6-inch refector (or Name: Mars larger); B pencil; blending type of object: Planet stump; soft and hard coNSteLLatIoN: art erasers

Utopia

Mare Acidalium

type of object: Planet

Step 1 Make a swatch of B graphite on a small piece of paper. Then use your fngertip to evenly P smudge the graphite over your entire sketching circle. Next, use the ‘fat’ side of the pencil’s graphite to lightly and evenly shade any dark features you see.

Utopia

Sinus Sabaeus

Eden

Step 1

SyrtisMake a swatch of B graphite on a small piece Majorof paper. Then use your fngertip to evenly

smudge the graphite over your entire sketching circle. Next, use the ‘fat’ side of the pencil’s Mare graphite to lightly and evenly shade any dark Tyrrhenum features you see.

Iapygia Viridis

N

equIpmeNt: Aeria Hellas fIeLd of(orVIew ShowN: 6-inch refector Moab Syrtis Major 15 arcminutes; 400x magnifcation larger); B pencil; blending Sinus stump; soft and hard Meridiani Sinus Mare art erasers Sabaeus Tyrrhenum beSt tIme to SKetch: ike all of the naked-eye northIapygia or south and ‘F’ or ‘P’ for following 1-30 April, 11pm-2am BST Viridis planets in our Solar System, or preceding). Following and preceding (10pm-1am UT)

L

MarsShowN: has been known to fIeLd of VIew since ancient times 15 arcminutes;mankind 400x magnifcation

P

Step 2 Soften the dark features with a blending stump (small, circular motions work best). To complete the shading process, you’ll need to darken some areas. Do this by rubbing the blending stump on the graphite swatch, and using it like a pencil to bring out the darker areas.

areHellas used instead of east and west to avoid confusion, because when Mars is viewed – Egyptian astronomers knew of its from the UK, its eastern limb faces retrograde motion by 1534 BC. When towards the western horizon. ike all of the naked-eye north or south and ‘F’ or ‘P’ for following Step 2 Galileo viewed it through his telescope Colour flters are useful for viewing Soften the dark features with a blending stump planets in our Solar System, or preceding). Following and preceding N (small, over 3,000 years wetofnally hadarea used instead Mars. Casual observers a fewmotions of work best). To complete Mars has beenlater, known of east and west to avoid often usecircular the shading process, you’ll need to darken since ancient times been confusion, because when Mars is contrast viewed and enhance closermankind look at Mars and we’ve them to increase some areas. Do this by rubbing the blending – Egyptian astronomers knew of its from the UK, its eastern limb faces stump onMars the graphite swatch, and using it like studying it ever since. clouds or dust storms. Advanced retrograde motion by 1534 BC. When towards the western horizon. a pencil to bring out the darker areas. This month, Mars’s observers use wider variety of flters to Galileo viewed it through his opposition telescope Colour flters are useful foraviewing N occurs at 20:57 UT on the 8th; the planet help them detect over 3,000 years later, we fnally had a Mars. Casual observers often use details a few of of the features closer lookits at Mars andapproach we’ve been to Earth,them contrast and enhance makes closest at a to increase they’re studying. If you don’t have any studying it ever clouds storms. Advanced P distance of since. 92,386,484km, on the 14th at or dust flters, don’t worryMars – just take your time This month, Mars’s opposition observers use a wider variety of flters to 12:54 UT. Mars’s size and magnitude will and sketch what you see. occurs at 20:57 UT on the 8th; the planet help them detect details of the features fuctuate during the month, but not Usually we include makes its closest approach to Earth, at a they’re studying. If you don’t have any everything in the enough to affect your when sketching, but use P distance of 92,386,484km, onchoice the 14thof at sketching flters, don’t eyepiece’s worry – justview take your time 12:54 UT. Different Mars’s size and magnitude and sketch what see. circle to represent Mars – this dates. features will will come into youryou entire fuctuate during thesomonth, Usually weway, include everything theft in all the details view though, what but younot see might not you’ll be ableinto enough to affect your choice of sketching eyepiece’s view when sketching, but use be the same as what’s shown here. your entire circle you see. If you want your sketch to look dates. Different features will come into to represent Mars – this here way more like what you see in the eyepiece, view Mars though,issoshown what you see the might notit appears way, you’ll be able to ft in all the details Step 3 to the naked-eye at culmination: north is blacken the background be the same as what’s shown here. you see. If you want your sketch to look sky. Do this with Indicate Mars’s bright areas by removing the Mars is shown here the way it appears more like what you see in the eyepiece, up and surface features rotate from left to a 9B pencil, black permanent marker or a background shading. For bright areas with a to the naked-eye at culmination: north is blacken the background sky. Do this with Step 3 right (from the following limb towards photo-editing program. Indicate Mars’s bright areas by removing the diffuse edge, round the tip of a soft eraser and up and surface features rotate from left to a 9B pencil, black permanent marker or a background shading. For bright areas with a the preceding limb). Different telescopes ‘dab’ the graphite away. For bright areas with right (from the following limb towards photo-editing program. edge, round the tip of a soft eraser and different views telescopes though, so be sure Carol Lakomiak is BBC Skydiffuse at Night thepresent preceding limb). Different distinct edge,with cut the end of a hard eraser so ‘dab’ the graphite away.aFor bright areas present different though, be sure Carol Lakomiak is BBC Skysketching at Night expert it is and use so it to ‘carve’ the graphite away. to mark yourviews sketch withso‘N’ or ‘S’ for Magazine’s a distinct edge, cut the end of fat a hard eraser

all pictures: carol lakomiak

L

all pictures: carol lakomiak

P

to mark your sketch with ‘N’ or ‘S’ for

Magazine’s sketching expert

it is fat and use it to ‘carve’ the graphite away.



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102 ED

Plossl 15mm (1.25”) .............................................................. £14.99 Plossl 20mm (1.25”) .............................................................. £14.99 Plossl 25mm (1.25”) .............................................................. £17.99 Plossl 30mm (1.25”) .............................................................. £17.99 with 2” SWA eyepice, Plossl 40mm (1.25”) ............................................................. £19.99 EYEPIECES/ACCESSORIES 2” 90M and 8.5x50 illuminated fnder Super Wide angle 10mm (1.25”) ....................................... £39.99 Plossl 5mm (1.25”) ................................................................. £14.99 Super Wide angle 20mm (1.25”) ....................................... £44.99 Plossl 10mm (1.25”) .............................................................. £14.99 Plossl 15mm (1.25”) (1.25”) .............................................................. £14.99 FF 8mm ....................................................................... £49.99 Plossl 20mm (1.25”) .............................................................. £14.99 FF 12mm (1.25”) .................................................................... £49.99telescope outft Plossl 25mm (1.25”) .............................................................. £17.99 FF 19mm (1.25”) .................................................................... £49.99 Plossl 30mm (1.25”) .............................................................. £17.99 FF 27mm (1.25”) .................................................................... £49.99with 2” SWA eyepice, Plossl 40mm (1.25”) ............................................................. £19.99 SWA 26mm ..................................................................... £79.992” 90M and 8.5x50 illuminated fnder Super Wide angle (2”) 10mm (1.25”) ....................................... £39.99 Super Wide angle (2”) 20mm (1.25”) ....................................... £44.99 SWA 32mm ..................................................................... £79.99 FF SWA 8mm (1.25”) ....................................................................... £49.99 38mm (2”) ..................................................................... £79.99 FF SWA82 12mm (1.25”) .................................................................... £49.99 8.8mm (1.25”) ...................................................... £129.99 FF 19mm (1.25”) .................................................................... £49.99 14mm (1.25”) ....................................................... £149.99 FF SWA82 27mm (1.25”) .................................................................... £49.99 SWA 26mm (2”) ..................................................................... £79.99 SWA82 24mm (2”) ............................................................. £199.99

telescope outft

Eyepieces & Accessories

102 ED£799.00

£799.00

HUGE RANGE

SWA 32mm (2”) ..................................................................... £79.99 SWA 38mm (2”) ..................................................................... £79.99 SWA82 8.8mm (1.25”) ...................................................... £129.99 SWA82 14mm (1.25”) ....................................................... £149.99 SWA82 24mm (2”) ............................................................. £199.99

of eyepieces HUGE RANGEand accessories

of eyepieces and accessories

Clearview Binoculars: Four Square Chapel, Mapplewell. S75 6GG. Tel 01226 383736.

www.clearviewbinoculars.co.uk Callers very welcome, please check website for opening times. Clearview Binoculars: Four Square Chapel, Mapplewell. S75 6GG. Tel 01226 383736. www.clearviewbinoculars.co.uk Callers very welcome, please check website for opening times. Binocular Outlet. Check our website or visit us at our shows throughout the UK. Binocular Outlet. Check our website or visit us at our shows throughout the UK. www.binocularoutlet.co.uk

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The Far-Sighted binocular company is a group of independent specialist optical goods suppliers. For more information please visit www.far-sighted.co.uk. TheOffers Far-Sighted binoculartocompany is a group specialist optical suppliers. For more information please visit www.far-sighted.co.uk. are subject availability and of atindependent participating outlets only.goods Prices and specifcations are subject to change without notice. Offers are subject to availability and at participating outlets only. Prices and specifcations are subject to change without notice.

skills APRIL 95

SKILLS

Scope With Steve Richards

dOctOr

StEVE’S TOP TIP

for the best way to store my telescope What’s skills APRIL 95 long periods of time? scope is careful long-term storage of a tele in good important to ensure that it remains moisture condition and ready for use. dust and choose uld sho are the greatest concerns, so you ted but not somewhere that is dry, well-ventila s to keep too warm and then take precaution tube is fully ser dust at bay. ensure that the focu and that retracted and ftted with a dust cap scope is also ftted with a telefor the front of thecope What’s the best way to store my teles inal cap, dust cap. if you don’t have the orig long periods of time? . can hat is often be used instead cope DaviD Frampton a teles of wer long-term storaagesho

SKILLS Our resident equipment specialist cures your

Scope

optical ailments and technical maladies

Which eyepieces are suitable for StEVE’S TOP TIP Maksutov-Cassegrains and how can I ensure the widest feld of view? With Steve Richards careful

dOctOr

in good important to ensure that it remains moisture and dust use. for y read and ition be used to observe globularcond clusters choose ld shou you are the greatest concerns, so not and many galaxies but the som high but d tilate -ven well ewhere that is dry, keep to ns autio prec take Will the Orion Mini-Guider be enough magnifcation Maksutov-Cassegrains then too warm and tube is fully ser focu the that re ensu bay. at are capable of can result in dust quite a guide my Celestron VX8 or do I need and that retracted and ftted with a dust cap narrow feld of view. something bigger? with a Keith moore the front of the telescope is also ftted cap, inal orig the Some of the latest Maksutovhave t don’ dust cap. if you ad. inste used be often can hat er Cassegrain telescopes can physically DaviD Frampton Finder-guiders like the Orion a show

to within a short optical tube by using a folded light path. The design requires Which eyepieces are suitable for a meniscus correcting lens at the front Maksutov-Cassegrains and how can of the instrument. These can be quite thick and heavy, so tend to feld limit the I ensure the widest of view? maximum aperture size of amateur take wide-feld 2-inch eyepieces. But Mini-Guider, Altair Astro 60mm Maksutov-Cassegrain telescopes are be used to observe globular clusters instruments to less than 8 inches. it’s worth bearing in mind that if the Miniguider or Altair Astro designed to give a long focal length and many galaxies but the high Typical focal ratios are in the region telescope’s rear aperture is narrower Finderscope (pictured Will the Orion Mini-Guider be enough to right) within a short optical tube by using a magnifcation Maksutov-Cassegrains of f/12 f/15, sodesign a typical 5-inchare capable than eyepiece’s that have been modifed folded lightto path. The requires of canthe result in quite a feld stop, guideyou my Celestron VX8 or do I need a meniscus correcting lens atathe frontlength narrow feldmay of view. telescope would have focal not achieve a fully illuminated something bigger?with Keithspecial mooreadaptor rings of of thearound instrument. These canwhile be quite Some of the latest 1,500mm, an feld of Maksutovview. are becoming very popular thick and heavy, so tend to limit the Cassegrain telescopes can physically Finder-guiders like the Orion 8-inch version would have a focal Ideal eyepieces would be either the for autoguiding mounts maximum aperture size of amateur take wide-feld 2-inch eyepieces. But Mini-Guider, Altair Astro 60mm length around 2,700mm. 1.25-inch 24mm Panopticor Altairwhen instruments to less than 8 inches.Focal it’s worth bearing in mind that ifTele the VueMiniguider Astro imaging deep-sky objects. lengths of this size give quite high or the Baader Hyperion 24mm, both Their Typical focal ratios are in the region telescope’s rear aperture is narrower Finderscope (pictured right)lightness and compact of magnifcation f/12 to f/15, so a typical than the eyepiece’s feldhave stop,ayou that have with 5-inch a given eyepiece of which 68° apparent feldbeen of modifed dimensions, combined with close coupling telescope would have a focal length may not achieve with special adaptor to rings making Maksutov-Cassegrains view.a fully The illuminated use of a focal reducer with the imaging telescope, which reduces the risk of of around 1,500mm, while an feld of view. are becoming very popular most suitable for Solar System this design is not recommended. fexure, makes them a compelling purchase. The 8-inch version would have a focal Ideal eyepieces would be either the for autoguiding mounts observing. However, they can also wide feld of view afforded by these diminutive length around 2,700mm. Focal 1.25-inch 24mm Tele Vue Panoptic when imaging deep-sky objects. lengths of this size give quite high or the Baader Hyperion 24mm, both Their lightness and compact guide telescopes also makes the task of locating Primary mirror magnifcation with a given eyepiece of which have a 68° apparent feld of dimensions, combined with coupling Starlight suitableclose guide stars easy. making Maksutov-Cassegrains view. The use of a focal reducer with Eyepiece to the imaging telescope, which reduces the risk of With the sub-pixel guiding accuracy provided most suitable for Solar System this design is not recommended. fexure, makes them a compelling purchase. The by modern Meniscus lens observing. However, they can also wide feld of view afforded by theseautoguiding diminutive software, even the short of locating these mini-guiders can be used guide telescopes alsofocal makeslengths the task of Primary mirror Starlight suitable guide stars easy. to guide imaging telescopes with focal lengths Eyepiece Coated With the spot sub-pixelof guiding accuracy provided over 1,200mm. Meniscus lens by modern autoguiding software, even the short The Celestron VX8 is available as either an 8-inch focal lengths of these mini-guiders can be used Newtonian Refector to guide imaging telescopes with focal lengths with a focal length of Coated spot 1,000mm or an 8-inch Schmidt-Cassegrain with a of over 1,200mm. Starlight The Celestron VX8focal is available as either an 8-inchThese mini-guiders would length of 2,032mm. Newtonian Refectorbe with a focal length of suitable for the Newtonian but for the Schmidt1,000mm or an 8-inch Schmidt-Cassegrain with a Starlight Cassegrain, an 80mm refractor or off-axis guider focal length of 2,032mm. These mini-guiders would would bebutrequired for guiding. be suitable for the Newtonian for the Schmidt-

maksutov cassegrain illustration by paul wootton, paul whitfield

maksutov cassegrain illustration by paul wootton, paul whitfield

Our resident equipment cures your Maksutov-Cassegrain telescopes specialist are designedailments to give a longand focal technical length optical maladies

Cassegrain, an 80mm refractor or off-axis guider would be required for guiding. Steve richards is a keen

Þ Maksutov-Cassegrains fold the light path to increase the scope’s focal length Þ Maksutov-Cassegrains fold the light path to increase the scope’s focal length

astro imager and an astronomy equipment expert

Steve richards is a keen astro imager and an astronomy equipment expert

Email your queries to [email protected]

Email your queries to [email protected]



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Our HI-LUX coating can be applied to almost any reflector, in virtually any condition or no matter how High Reflectivity old. Improves the reflective efficiency of your mirrors. Coating Find out more on our website: Optics > Mirror Recoating or call / email

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REVIEWS APRIL 97

Reviews Bringing you each month,

HOW WE RATE Each category is given a mark out of fve stars according to how well it performs. The ratings are:

★★★★★ Outstanding ★★★★★ Very good ★★★★★ Good the best in equipment and accessoriesREVIEWS APRIL ★★★★★ Average 97 ★★★★★ Poor/Avoid as reviewed by our team of astro experts

Reviews SEE INTERACTIVE 360° MODELS OF

Bringing youLIGHT the REVIEWS best inATequipment and accessories ALL OUR FIRST WWW.SKYATNIGHTMAGAZINE.COM each month, as reviewed by our team of astro experts

HOW WE RATE Each category is given a mark out of fve stars according to how well it performs. The ratings are:

★★★★★ Outstanding ★★★★★ Very good ★★★★★ Good ★★★★★ Average ★★★★★ Poor/Avoid

This month’s reviews SEE INTERACTIVE 360° MODELS OF light ALLFirst OUR FIRST LIGHT REVIEWS AT

WWW.SKYATNIGHTMAGAZINE.COM

98

Meade LX600-ACF 12-inch SchmidtThis month’sCassegrain

reviews First light

102

William Optics GTF 102 fveMeade LX600-ACF element astrograph

98

12-inch SchmidtCassegrain

Tried & tested William

102

Optics QSI 683 GTF 102 fveelement astrographWSG-8

106

CCD camera with in-built flter wheel Tried & tested

98

683 Books106 QSI WSG-8

CCD camera with in-built flter wheelWe

Books

Gear WWW.ThESECrETSTuDIO.nET X 4

WWW.ThESECrETSTuDIO.nET X 4

Gear

110

rate four of the latest astronomy titles

110

We rate four of the latest astronomy titles

98

Find out how the huge Meade LX600 improves on its forebears

Find out how the huge Meade LX600 improves on its forebears

112

Including this Baader Classic Including Q-Eyepiece Set this

112

Baader Classic Q-Eyepiece Set

Find out more about how we review equipment at:

Find out more about how we review equipment at: www.skyatnightmagazine.com/scoring-categories www.skyatnightmagazine.com/scoring-categories skyatnightmagazine.com 2014


98

first light

see an interactive 360° model of this scope at www.skyatnightmagazine.com/meadelx600

Meade LX600-ACF 12-inch

98

Schmidt-Cassegrain first light see an interactive 360° model of this scope at www.skyatnightmagazine.com/meadelx600

smart upgrades and refnements characterise this huge telescope

words: pete lawrence

Meade LX600-ACF 12-inch ViTAl STATS

Sky SAyS… he Meade LX600 is, in the A bridge connection, via a pair of manufacturer’s words, a giant nine-pin D-plug leads, is required to The Meade leap forward in telescope allow the Go-To computer at the base LX600 is a • Price £5,760 with design, creating a portable, of the forks to communicate with the formidable X-Wedge, £5,280 highly transportable and easy to set up declination drives across the fork without imaging platform platform for observation and breaks. Another eight fddly thumb 305mm smart upgrades and refnements characterise this hugedespite telescope • Aperture its fddly astrophotography. We put that to the test screws need to be tightened to ensure (12 inches) words: pete lawrence set-up process in this review of the 12-inch variant. a good connection. • Focal length In this style of telescope, the tube is Our test setup included a sturdy 2,438mm (f/8) Sky SAyS… he Meade LX600 is, in the A bridge connection, via a pair of Internal dual incorporated heavy-duty feld tripod,towhich is included, and an ViTAl STATS • Focuser manufacturer’swithin words, aagiant nine-pin D-plug leads, is required The fork Meade speed 7:1 Crayford-style mounting assembly. A Go-To computer is ftted allow the optional Meade X-Wedge. leap forward in telescope Go-To computer at the base This is a satisfyingly solid, LX600 is a £5,760 with Field tripod • Price Giant • Mount design, creating a portable, of the forks to communicate with in the base of the mount. Lifting this arrangement angled platform used tothe convert the LX600’s altaz fork formidable X-Wedge, £5,280 Controller Autostar II highly transportable and easy to set up declination drives across the fork • onto a tripod or equatorial wedge is notplatform for the mount to equatorial mode for long-exposure imaging. without imaging for observation and breaks. Another eight fddly thumb • Additional 305mmfeatures platformfainthearted, • Aperture although the design of the LX600 despite its fddly screws need to be tightened to ensure (12GPS, inches)True Level and astrophotography. We put that to the test does include a means to split the fork arms, so set-up process in this review of the 12-inch variant. a good connection. length • Focal North sensors, time chip, In this style of telescope, the tube is OurThe test setup included a sturdy reducing the component lifting weight. LX600 includes a new feature known as 2,438mm (f/8) planetarium software incorporated within a heavy-duty fork feld tripod, which is included, and an high-precision pointing • Focuser Internal dual There are two arm stubs fxed to the optical StarLock, which enables Telescope tube • Weight speed 7:1 Crayford-style mounting assembly. A Go-To computer is ftted optional Meade X-Wedge. This is a satisfyingly solid, tube – these connect to the main forks via two accuracy and autoguiding functionality. For 16.3kg, drive base Giant Field tripod • Mount in the base of the mount. Lifting this arrangement angled platform used to convert the LX600’s altaz fork with fork armsII 22.7kg, bolted plates. Awedge locating for each Autostar StarLock to work correctly, • Controller onto a tripod or equatorial is notpin for is theprovidedmount to equatorial mode for long-exposure imaging. the telescope tube must • Additional tripod features 22.7kg plate. One arm stub can’t be locked and swings be well balanced. Rail-mounted counterweights fainthearted, although the design of the LX600 GPS, True Level and • Supplier Telescope House does include a means to split the fork it arms, pointing freely, making locating thatsobit harderHigh-precision to ft. are provided to achieve this, but they require a North sensors, time chip, reducingOnce the component weight. The LX600 includes ahex newkey feature known their as • www.telescopehouse. planetarium software in placelifting we found it fddly and timeto adjust position – thumb screws There are two arm stubs fxed to the optical StarLock, which enables high-precision pointing comTelescope tube • Weight consuming to ft all eight of the locking hex bolts would have been better. We also found that we accuracy and autoguiding functionality. For 16.3kg, drive base 837610 tube – these connect to the main forks via two • Tel 01342 and washers in place, and far too easy to drop had tothe adjust ourtube guide rate to fairly low to stop with fork arms 22.7kg, bolted plates. A locating pin is provided for each StarLock to work correctly, telescope must tripod 22.7kg them. In the this and wasswings frustrating. be well balanced. Rail-mounted the StarLock from overcompensating. > plate. One arm stub can’tdark be locked counterweights

T Schmidt-Cassegrain T

www.thesecretstudio.net x 3

www.thesecretstudio.net x 3

High-precision pointing

• Supplier Telescope House • www.telescopehouse. com • Tel 01342 837610

freely, making locating it that bit harder to ft. Once in place we found it fddly and timeconsuming to ft all eight of the locking hex bolts and washers in place, and far too easy to drop them. In the dark this was frustrating.

are provided to achieve this, but they require a hex key to adjust their position – thumb screws would have been better. We also found that we had to adjust our guide rate to fairly low to stop the StarLock from overcompensating. >

stellar starlock

The most innovative aspect of the LX600 system is StarLock. This comprises a wide-feld, 14.7º by 11.8º camera for general pointing and a 3-inch f/5 telescope, giving a 57.2 arcminute by 45.8 arcminute autoguiding setup. stellar starlock The StarLock assembly unobtrusively locks onto the main telescope tube The most innovative aspect of the LX600 is StarLock. This comprises and is connected tosystem the main computer via a supplied cable. a wide-feld, 14.7º by 11.8º camera for general pointing and a 3-inch f/5 Upon activating the Go-To, the wide-feld camera automatically locates telescope, giving a 57.2 arcminute by 45.8 arcminute autoguiding setup. a nearby bright locks star, onto which initially centred. The StarLock assembly unobtrusively the is main telescope tube The scope then slews to the selected object, at which point the autoguider locks on. The whole process and is connected to the main computer via a supplied cable. Upon activating the Go-To, the wide-feld automatically takes a bit longer than camera a direct Go-To, butlocates the accuracy is better as a result. a nearby bright star, which isisinitially centred. scope thenarcsecond slews to the guiding accuracy, although StarLock described asThe producing selected object, at which point the autoguider locks on. The whole process conditions and set-up precision may affect this. takes a bit longer than a direct Go-To, but the accuracy is better as a result. system’s arcsecond activity isguiding indicated by aalthough rather comforting red LED. Once StarLock is describedThe as producing accuracy, we’d balanced the optical tube and set the guide rate, the system did the conditions and set-up precision may affect this. The system’s activity is indicated by a rather comforting red LED. Once rest. Thanks to StarLock, the LX600 range offers large aperture telescopes we’d balanced thewith optical tube and set the guide rate,capability the system did theautoguiding for long-exposure camera-enhanced Go-To and rest. Thanks to StarLock, the LX600 range offers large aperture telescopes astrophotography. That’s a pretty exciting prospect. with camera-enhanced Go-To capability and autoguiding for long-exposure astrophotography. That’s a pretty exciting prospect.

first light april 99

Zero-SHiFT FoCuSer

SpLiT-Fork deSign Like the LX200 range before it, LX600 telescopes are heavy. Meade has engineered a clever way to separate the optical tube from the main forks, allowing the 12-inch LX600 to be just about assembled by one person. However, certain SpLiT-Fork design aspects make the deSign process of putting the scope together Likeback the LX200 rangea bit fddly.

Meade has redesigned its old LX-range focuser to produce a new mechanism that keeps the target frmly in view while focus is adjusted. This overcomes a shortcoming of previous designs where the image could shift out of view as the focus was adjusted. The new design offers coarse first light april 99 and fne (7:1) focus options.

Zero-SHiFT FoCuSer Meade has redesigned its old LX-range focuser to produce a new mechanism that keeps the target frmly in view while focus is adjusted. This overcomes a shortcoming of previous designs where the image could shift out of view as the focus was adjusted. The new design offers coarse and fne (7:1) focus options.

before it, LX600 telescopes are heavy. Meade has engineered a clever way to separate the optical tube from the main forks, allowing the 12-inch LX600 to be just about assembled by one person. However, certain design aspects make the process of putting the scope back together a bit fddly.

X-Wedge Meade’s newest equatorial wedge, this heavy-duty platform tilts the base of the LX600 forks so that the RA axis points at the north celestial pole. Fine adjustment X-Wedge is made through altitude Meade’s newest equatorial and azimuth knobs. wedge, this heavy-duty platform tilts the base of the LX600 forks so that the RA axis points at the north celestial pole. Fine adjustment is made through altitude and azimuth knobs.

AuToSTAr ii CoMpuTeriSed go-To As with earlier models, the LX600 is equipped with the Meade Autostar II AuToSTAr ii CoMpuTeriSed go-To computerised controller. This system gives you telescope set-up and which

As with earlier models, the LX600 equipped with the Meade Autostar IIobjects, confguration options, asiswell as a database of 145,000 computerised controller. This system gives you telescope set-up and can be centred on at the touch of a few buttons. confguration options, as well as a database of 145,000 objects, which can be centred on at the touch of a few buttons.



100 first light april

first light F/8 opTiCS Another departure from earlier LX200 models is the use of f/8 rather than f/10 optics. This delivers a wider and brighter feld of view, allowing the scope to produce decent images of deep-sky objects as well as still keeping a good image scale for Solar System imaging and viewing.

100 first light april

> The Advanced Coma-Free (ACF) optics are a

first light

delight to use. A view of the Orion Nebula gave lots of beautiful detail in the swirling gas cloud, while theopTiCS tight trapezium star cluster took the guise of F/8 diamonds scattered in ‘cotton wool’. Dark mottles Another departure from earlier LX200 models is the use of edges of the nebula stooda out in the f/8and rather than f/10 optics. This delivers widersuperbly and brighter feld of view, allowingview the scope decent high-contrast andtoitproduce was easy to images get lostof in the deep-sky objects as well as still keeping a good image scale sumptuous detail. Planetary imaging with the LX600 for Solar System imaging and viewing. is really good, as StarLock helps to keep your target centred in the feld of view. This would be a dream > The Advanced Coma-Free (ACF) optics are a system for taking planetary timelapse sequences. delight to use. A view of the Orion Nebula gave lots A major criticism of previous LX models was the of beautiful detail in the swirling gas cloud, while shift caused by thetook focuser. This theimage tight trapezium star cluster the guise of has been fxed diamonds ‘cotton wool’. has Darkbeen mottles for thescattered LX600 in – the focuser revamped and edges of the nebula stood out superbly in the completely – and we didn’t experience any image shift high-contrast view and it was easy to get lost in the whatsoever. The focus knob is a little stiff though, sumptuous detail. Planetary imaging with the LX600 so forgood, accurate high-magnifcation focusing we’d is really as StarLock helps to keep your target recommend inwould an in-line electric focuser. centred in the feldinvesting of view. This be a dream system for taking planetary timelapse sequences. A major criticism of previous LX models was the image shift caused by the focuser. This has been fxed The mount drives use large, 5.75-inch gears to help for the LX600 – the focuser has been revamped maintain accuracy provide movements completely – and we didn’tand experience anysmooth image shift whatsoever. focusperiodic knob is a little stiff though, great feature without The serious error. Another so of forthis accurate high-magnifcation we’d designed to setup is the way thatfocusing it has been recommend investing in an in-line electric focuser.

work from horizon-to-horizon without the need for a meridianimprovements fip as the scope passes through the Further north-south something thattosome The mount drives plane, use large, 5.75-inch gears help much more maintain accuracy and continue provide smooth movements expensive setups to experience. without serious periodic LX error. Another greatdesigns, feature the LX600 Unlike previous folded-optic of this setup is the way that it has been designed to is f/8 rather than f/10. This gives a bigger, brighter work from horizon-to-horizon without the need for image and a wider natural of view. a meridian fip as the scope passes feld through the It also reduces the tolerance north-south plane, required something to thatmaintain some muchgood morepointing expensive setups continue to experience. accuracy for long exposures. If you’re a planetary or Unlike the LX600 lunar previous imager,LX thefolded-optic generousdesigns, 2.4m focal length will still Sky SAyS… is f/8 rather than f/10. This gives a bigger, brighter offer good image scale without an optical amplifer. image and a wider natural feld of view. It also reduces Now add these: The Meade LX600 is a formidable astro-imaging the tolerance required to maintain good pointing 1. Meade zero accuracy for long exposures. If you’re a planetary platform despite its set-up process beingorawkward lunar imager, the generous 2.4m focal length will still Sky SAyS…image shift and a little fddly. Counterweight thumb screws offer good image scale without an optical amplifer. Now add these: Þ Starlock-guided M82 plus the January 2014 supernova instead of hex bolts and a better split-fork coupling microfocuser The Meade LX600 is a formidable astro-imaging would really help the system achieve its goal as a 1. Meade zero platform despite its set-up process being awkward 2. Explore S portable system. and a little fddly. Counterweight thumb screws image shift Þ Starlock-guided instead of hex bolts and a better split-fork coupling 3-inch M82 plus the January 2014 supernova microfocuserScientifc would really help the system achieve its goal as a 2. Explore 0.7x reducerportable system. S Verdict Scientifc 3-inch corrector ★★★★★ Build And deSign 0.7x reducer3. Revelation Verdict ★★★★★ corrector eASe OF uSe ★★★★★ Quartz 2-inch Build And deSign ★★★★★ FeATuReS 3. Revelation ★★★★★ eASe OF uSe dielectric diagonal Quartz 2-inch gO-TO/TRACking ACCuRACy★★★★★ ★★★★★ FeATuReS dielectric diagonal OPTiCS ★★★★★ ★★★★★ gO-TO/TRACking ACCuRACy ★★★★★ ★★★★★ OPTiCS OVeRAll Þ Our composite shot of M42 turned out beautifully

www.thesecretstudio.net, pete lawrence x 2

www.thesecretstudio.net, pete lawrence x 2

Further improvements

OVeRAll



★★★★★

Þ Our composite shot of M42 turned out beautifully

Observing the Sun through an h-alpha filter is an incredible experience… Solarscope manufacture complete h-alpha telescopes available in unobstructed 50mm and 60mm apertures as well as a range of h-alpha lter systems which can convert your existing astronomical telescope into a high quality solar instrument. H-alpha lter systems are available in unobstructed 50mm, 60mm, 70mm and 100mm aperture sizes.

Observing the Sun through an h-alpha filter is an incredible experience… The dedicated Solarview telescope range provides you with Solarscope manufacture complete(SV) h-alpha telescopes available in unobstructed 60mm aperturesthe as well of h-alpha everything50mm you and need to observe Sunasina range h-alpha apart from a mount and lter systems which can convert your existing astronomical telescope to intothe a highest clear skies! These solar instruments are manufactured high quality solar instrument. H-alpha lter systems are available in quality and will give you views of our nearest star which will literally take unobstructed 50mm, 60mm, 70mm and 100mm aperture sizes. your breath away.

The dedicated Solarview (SV) telescope range provides you with The solar lter system (SF) range consists offrom a totally unobstructed front mounted etalon with a matching rear mounted blocking lter which ts everything youneed to observe the Sun in h-alpha apart a mount and clear solar instruments areholder. manufactured to the made highestadapter plate is used to securely mount the etalon over the front of your telescope. Using intoskies! yourThese telescope’s eyepiece A custom quality and will give you views of our nearest star which will literally take laser industry techniques our lter systems are manufactured to the highest optical tolerances. your breath away. The solar lter system (SF) range consists of a totally unobstructed front mounted etalon with a matching rear mounted blocking lter which ts into your telescope’s eyepiece holder. A custom made adapter plate is used to securely mount the etalon over the front of your telescope. Using laser industry techniques our lter systems are manufactured to the highest optical tolerances.

Prestige hydrogen-alpha solar lters manufactured in the Isle of Man Prestige hydrogen-alpha solar lters manufactured in the Isle of Man

For information on Solarscope filters Contact: Ken Huggett

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07624 435572

07624 435572

[email protected]

[email protected]

www.solarscope.co.uk

www.solarscope.co.uk

102

first light

see an interactive 360° model of this telescope at www.skyatnightmagazine.com/wogtf102

William Optics GTF 102

fve-element astrograph

102

first light

see an interactive 360° model of this telescope at

An excitingwww.skyatnightmagazine.com/wogtf102 imaging scope that performs just as well visually

ViTAL STATS

words: steve richards

W astrograph fve-element

• Price £1,669 • Optics FPL53 triplet illiam Optics produces two versions image shift when we tightened up the locking bolt with rear two-element of its 4-inch apo refractor: one a once we had achieved focus. feld fattener conventional triplet lens and the The telescope produced a feld of view 1° and 54 • Aperture 102mm other a fve-element astrograph – it’s arcminutes wide by 1° and 16 arcminutes deep with (4 inches) the latter we’re reviewing here. The word astrograph our test camera, a one-shot-colour CCD with an • Focal length indicates that the telescope is designed with APS-C sensor. This area is just large enough to 703mm (f/6.9) astrophotography in mind. capture the Rosette Nebula and some surrounding 786mm with • LengthSTATS ViTAL It arrived in a standard cardboard box, but on stars. With a focal ratio of f/6.9, this telescope is dew shield extended,words: steve richards £1,669 with dew 659mm • Price opening that up we were greeted by a beautifully relatively slow compared to many astrographs, FPL53 triplet • Optics illiam Optics produces two versions image shift when we tightened up thehave locking bolt advantages – chromatic shield retracted made and sturdy case with ample padding to protect but this does some with rear two-element of its 4-inch apo refractor: one a once we had achieved focus. 2.5-inch • Focuser the telescope in transit. The instrument itself is aberration and feld curvature are slightly easier feld fattener conventional triplet lens and the The telescope produced a feld of view 1° and 54 dual-speed 10:1 • Aperture 102mm strikingly fnished in an toand control with longer focal length lenses. otherattractive, a fve-element astrograph – it’soff-white arcminutes wide by 1° 16 arcminutes deep with rack and pinion (4 inches) coat contrasting the latterstippled-powder we’re reviewing here. Thewith word three astrograph our testcerise camera, a one-shot-colour CCD with an lengthTube rings • Focal • Extras indicatesbands that theoftelescope is designed with APS-C sensor. This area is just large enough to anodised aluminium. 703mm (f/6.9) • Weight 5kg excludingastrophotography in mind. some surrounding • Length 786mm with William Optics has recently changedcapture from the Rosette Nebula As theand CCD camera we used for this review had an tube rings It arrived in a standard cardboard box, but on stars. With a focal ratio of f/6.9, this telescope is dew shield extended, using Crayford focusers to rack and pinion APS-C sensor, the star shapes in our images are a The • Supplier 659mm with dew opening that up we were greeted by a beautifully relatively slow compared to many astrographs, alternatives, andample the padding 2.5-inchtounit supplied good indicator for what to expect with a typical shield retracted Centre made and Widescreen sturdy case with protect but this does have some advantages – chromatic 2.5-inch • Focuser the telescope transit. The telescope instrument worked itself is smoothly aberration and feld curvature are slightly easierhas a very similarly sized withinthe review DSLR camera, which • www.widescreendual-speed 10:1 strikinglyand attractive, fnished in an off-white to control with longer focal length lenses. centre.co.uk fawlessly. With a maximum extension sensor. We were very pleasantly surprised by the rack and pinion stippled-powder coat with three contrasting cerise Tel 020 7935 2580 • of 80mm there is plenty of focus travel, but shape of the stars across the feld of view Extras Tube rings • bands of anodised aluminium. Shapely stars • Weight 5kg excluding notOptics knowing exactly where the sensor would and right intoreview the corners. William has recently changed from As the CCD camera we used for this had an The tube rings be when we achieved focus we inserted a 50.8mm two-element internal using Crayford focusers to rack and pinion APS-C sensor, the star shapes in our images arefeld a • Supplier The alternatives, and the 2.5-inch supplied goodoff-axis indicator for what to expect with a typical extension tube in unit front of our camera and fattener was certainly Widescreen Centre with the guider. review telescope workedout smoothly DSLRguess camera, whichdoing has a very similarly • www.widescreenThis turned to be a pretty good its job > sized centre.co.uk and fawlessly. With a maximum extension sensor. We were very pleasantly surprised by the – we achieved crisp focus at an extension of just • Tel 020 7935 2580 of 80mm there is plenty of focus travel, but shape of the stars across the feld of view 18mm, which of the focus tube not knowing exactly whereleft theplenty sensor would andwithin right into the corners. The focuserfocus for stability. be when the we achieved we inserted a 50.8mm two-element internal feld extension tube front of our camera and off-axis Theinfocuser easily handled the weightfattener of ourwas certainly guider. This turned out to be a pretty good guess doing its job > imaging system using both the coarse and fne focus – we achieved crisp focus at an extension of just knobs, and there was only the smallest amount of 18mm, which left plenty of the focus tube within the focuser for stability. The focuser easily handled the weight of our imaging system using both the coarse and fne focus knobs, and there was only the smallest amount of

William Optics GTF 102

W

all photos: www.thesecretstudio.net

all photos: www.thesecretstudio.net

An exciting imaging scope that performs just as well visually

Shapely stars

quintet of quality

The GTF 102 astrograph has an unusual optical system, comprising fve elements arranged in two groups. The primary lens is an air-spaced triplet that uses FPL53 extra-low dispersion quintet quality glass to bringof all the colours of light to the same focus point. This is important to avoid chromatic aberration, which results in system, unwanted coloured halos around The GTF 102 astrograph has an unusual optical comprising fve elements arrangedbright objects. The in two groups. primaryare lenshoused is an air-spaced triplet that uses FPL53 extra-low dispersion three lens The elements in a fully adjustable, CNC-machined lens cell. glass The to bring all thegroup coloursis of made light to up the of same focus This is important to avoid second two lenspoint. elements (also made from extra-low dispersion chromatic aberration, which results in unwanted coloured halos around bright objects. The glass), which are set inside the telescope tube. They act as a feld fattener to combat the three lens elements are housed in a fully adjustable, CNC-machined lens cell. feldsecond curvature is normally present in a(also refractor. Field curvature causes stars at the edges The group that is made up of two lens elements made from extra-low dispersion of the feld appear elongated, which a particular problem glass), which areofsetview insidetothe telescope tube. They act as a is feld fattener to combat the in deep-sky imaging. feld curvature that is normally present in a refractor. Field curvature causes starstransmission at the edges and reduce All of the lens surfaces are fully multicoated to increase light of unwanted the feld of view to appear elongated, which is a particular problem in deep-sky refections. Since the feld fattener is built in, there is no imaging. critical spacing issue All of the lens surfaces are fully multicoated to increase light transmission and reduce when using a camera, so installing a flter wheel and an off-axis guider is straightforward. unwanted refections. Since the feld fattener is built in, there is no critical spacing issue when using a camera, so installing a flter wheel and an off-axis guider is straightforward.



first light APRIL 103

TeleScOPe Tube The construction of the telescope tube, which is machined from aluminium, underpins the optical system’s stability – the whole telescope felt very solid indeed. Internally the tube is fnished in matt black and has three knife-edge baffes, which together help to reduce first light APRIL 103internal refections and increase the contrast of the view.

TeleScOPe Tube

Tube RinGS The 105mm diameter, CNC-machined tube rings have a crisp, black crackle fnish. With a choice of mounting holes in both upper and lower mountings, they accommodate various types of dovetail bar and accessories. Nylon spacers on the locking bolts help to protect the clamp surfaces.

The construction of the telescope tube, which is machined from aluminium, underpins the optical system’s stability – the whole telescope felt very solid indeed. Internally the tube is fnished in matt black and has three knife-edge baffes, which together help to reduce internal refections and increase the contrast of the view.

Tube RinGS The 105mm diameter, CNC-machined tube rings have a crisp, black crackle fnish. With a choice of mounting holes in both upper and lower mountings, they accommodate various types of dovetail bar and accessories. Nylon spacers on the locking bolts help to protect the clamp surfaces.

Rack and PiniOn FOcuSeR The 2.5-inch rack and pinion focuser has anti-marring brass compression rings, can be rotated Rack and PiniOn through 360° and is very smooth in operation, with minimal FOcuSeR image shift when applying the The 2.5-inch rack and pinion focuser has anti-marringsimple brass lock mechanism. The 10:1 mechanism handled compression rings, cantwo-speed be rotated through 360° and is very the weight of our imaging smooth in operation, with minimal camera, off-axis guider and image shift when applying the guide camera with ease. simple lock mechanism. The 10:1 two-speed mechanism handled the weight of our imaging camera, off-axis guider and guide camera with ease.

Sky SAyS… All of the lens surfaces are fully multicoated to increase light transmission and reduce unwanted refections

Sky SAyS… All of the lens surfaces are fully multicoated to increase light ReTRacTable deW Shield transmission and The 127mm-long dew shield does an excellent job of defecting extraneous ReTRacTable deW Shield reducelight unwanted and keeping the dew at bay. The front is capped with an aluminium dust cover The 127mm-long dew shield does an excellent job of defecting extraneous light refections thatthe simply slips on and off. convenient thumbscrew and keeping dew atand bay.safely The front is capped with anA aluminium dust cover inand its extended position. that simply safely slips on and off. A convenient thumbscrew locks the shield in its extended position.

locks the shield



104 first light APRIL

first light 104 first light APRIL

first light

The GTF 102 is supplied > and so too was the triplet lens, as chromatic with a high-quality soft aberration was also well controlled. There was padded case. It is very some vignetting, which caused the edges of the substantial and protects feld of view to be darker than the centre, but this the telescope in transit was easily corrected by calibrating the images very well indeed. With SOFT caSe with suitable fat frames. One problem that can both carry handles and a multi-element designs like this is Theshoulder GTF 102 strap, is supplied > and so occur too waswith the triplet lens, as chromatic transporting with a high-quality soft aberration wasofalso well shift controlled. was that focus withThere temperature change. the scope is easy. padded case. It is very some vignetting, which caused the edges of the However, we didn’t fnd it necessary to adjust substantial and protects feld of view to be darker than the centre, but this focus during our 4.5-hour imaging session the telescope in transit was easily corrected by calibrating the images very well indeed. With despite a thickOne frost forming on the inside of with suitable fat frames. problem that can both carry handles and a ourmulti-element domed observatory. occur with designs like this is shoulder strap, transporting that of focus shift with temperature change. Although the GTF 102 is designed as an the scope is easy. However,astrograph, we didn’t fndwe it necessary adjustusing it for some couldn’ttoresist focus during our 4.5-hour imaging session observing and we weren’t disappointed. thick frost forming on the inside of Sky SAyS… despite asimple Using our own 2-inch dielectric diagonal and our domed observatory. Now add these: Although the GTFwe 102enjoyed is designed as anglorious views of eyepieces some astrograph, we couldn’t resist using it Moon. for some Jupiter and the gibbous 1. William simple observing and we weren’t disappointed. Sky SAyS…50mm The lack of false colour in our imaging tests was Optics Using our own 2-inch dielectric diagonal and Now add these: corroborated through Confrmed too eyepieces we enjoyed some glorious the viewseyepiece. of Þ Our image of the rosette nebula in monoceros guidescope with were star shapes right out to the edge of Jupiter and theexcellent gibbous Moon. 1. William exhibits clean star shapes right to the edges of the feld mounting bracketThe lack false colour in our tests was the presence theoffeld of view. Weimaging couldn’t ignore Optics 50mm corroborated through the eyepiece. Confrmed tooswathe of the Orion Nebula and the large of image of the rosette nebula in monoceros Þ Our guidescope with 2. Atik 383L+ were excellent star shapes right out to the edge of exhibits clean star shapes right to the edges of the feld nebulosity observed through our 17mm eyepiece mounting bracket the feld of view. We couldn’t ignore the presence CCD camera wasNebula particularly ★★★★★ of the Orion and the memorable, large swathe of as was the crisp, BuiLd And dESign 2. Atik 383L+ 3. Sky-Watcher nebulosity Verdict sparkly view of the Pleiades star cluster. observed through our 17mm eyepiece ★★★★★ CCD camera EASE OF uSE memorable, asenjoyed was the crisp, ★★★★★ AZ-EQ6 GT was particularly We thoroughly our experiences with thedESign BuiLd And ★★★★★ FEATurES 3. Sky-Watcher sparkly view of the Pleiades star cluster. ★★★★★ EASE OFtouSE GTF 102 and would recommend the telescope mount and tripod AZ-EQ6 GT We thoroughly enjoyed our experiences with the ★★★★★ imAging QuALiTy ★★★★★ any astrophotographer searching for an FEATurES imaging GTF 102 and would recommend the telescope to mount and tripod ★★★★★ ★★★★★ imAging QuALiTy OPTicS instrument that removes pain of achieving a fat any astrophotographer searching for anthe imaging ★★★★★ ★★★★★ OVErALL instrument that removes pain of achieving fat S OPTicS feld with starsthepin sharp to the aedge. ★★★★★ OVErALL feld with stars pin sharp to the edge. S

www.thesecretstudio.net, steve richards

www.thesecretstudio.net, steve richards

SOFT caSe

Verdict



f1telescopes

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Part large range of telescopes andneeds. accessories from the world’s leading suppliers. for ALLA your astronomy we also buy and sell usedcheck telescopes Tel: 01903 247317 • 16 Mulberry Lane, Goring-by-Sea, Worthing, West Sussex out ourand website: Celestron, Sky-Watcher, provide service and repair facilities. www.f1telescopes.co.uk www.sussex-astronomy-centre.co.uk visit our shop at: unit a3, st GeorGe’s Business Park, Castle road, sittinGBourne, kent me10 3tB. 01795 432702 check out our website:

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106

Tried & tested

We review well-established equipment that’s stood the test of time

QSI 683

ViTal STaTS

106

see an interactive 360° model of this camera at www.skyatnightmagazine.com/ qsi683

WSG-8

• Price £3,149 • Size 141x149x84mm • Sensor Truesense see an interactive Imaging KAF-8300 360° model of this camera at • Sensor size www.skyatnightmagazine.com/ We17.96x13.52mm, review well-established equipment that’s stood the test of time qsi683 22.5mm diagonal • Pixels 3326 x 2504 • Back focus 50.2mm words: steve richards Weight 1.66kg • ViTal STaTS strophotography has rightly become along with an ASCOM driver and a full set • Extras Peli case, £3,149 • Price AC mains power a very important and enjoyable aspect of well-written and comprehensive manuals. 141x149x84mm • Sizesupply, USB cable, of astronomy: it is only through Plug-ins for other image capture programs are • Sensor Truesense ST4 cable, Allen keys, the capture of long-exposure images available for download from the QSI website Imaging KAF-8300 2-inch nosepiece Sensor size • that the true colourful beauty and detail of (www.QSimaging.com). 17.96x13.52mm, adaptor, CD deep-sky objects can be appreciated. Modern 22.5mm diagonal Ian King • Supplier DSLR cameras can capture this detail and much 3326 x 2504 • Pixels Imaging • Back focus 50.2mm words: richards ofsteve the colour of these objects, but dedicated At 1.66kg, the camera feels very substantially built • www.iankingimaging. 1.66kg • Weight astronomical CCDs the QSI 683along WSG-8 and closer confrms the quality of the comPeli case, strophotography has such rightlyas become with an ASCOM driver andinspection a full set • Extras cana do much better. This isaspect because they have manufacturing. Great attention to detail has been AC mains power212356 veryitimportant and enjoyable of well-written and comprehensive manuals. 01580 • Tel supply, USB cable, of astronomy: is only through capture on programs are external case and the built-in coolingit to reduce thermal noisePlug-ins from for theother image expended both the ST4 cable, Allen keys, the capture of long-exposure images available for download from the QSI website sensor and are not hampered by infrared flters internal components, and we couldn’t help but 2-inch nosepiece that the true colourful beauty and detail of (www.QSimaging.com). designed for daytime use. be impressed with how it all ftted together. The adaptor, CD deep-sky objects can be appreciated. Modern • Supplier Ian King Thecan QSI 683 WSG-8 camera, frst releasedmanufacturing built-in flter wheel possesses eight slots, which we DSLR cameras capture this detailCCD and much Quality Imaging of the colour of these objects, but dedicated in 2012, is designed to overcome several of the At 1.66kg, the camera feels very substantially built flters: luminance, red, populated with our own • www.iankingimaging. Sky SayS… astronomical CCDs such as the QSI 683 WSG-8 and closer inspection confrms the quality of the issues that cause the most angst among astro green, blue, hydrogen-alpha, oxygen III, sulphur II com much better. This is because they have attention to detail has been a can do itimagers. 01580 imaged 212356 • TelWe The inclusion of an integratedmanufacturing. flter wheel Greatand hydrogen-beta. Having such a variety of flters built-in cooling to reduce thermal noise from the expended on both the external case and the range of objects and guider withflters enough space to use at onehelp time sensor and arean notoff-axis hampered by infrared internal components,available and we couldn’t butmakes for very fexible and were very designedwith a standard coma corrector, feld fattener or imaging as it is easy to choose the right flter for for daytime use. be impressed with how it all ftted together. The 683 reducer WSG-8 CCD camera, frst released eight slots, which we focal is one of these good ideas.built-in flter wheel possesses the celestial object at hand. impressed with The QSI in 2012, is designed to overcome several in of the populated with our ownDeep-sky flters: luminance, red, The camera is supplied a high-quality Peli imaging requires long exposures, so Sky theSayS… sensitivity issues that cause the most angst among astro green, blue, hydrogen-alpha, oxygen III, sulphur II 1400 case, giving the contents excellent protection. it is imperative to ensure that your mount tracks We imaged and lackaof imagers. The inclusion of an integrated flter wheel and hydrogen-beta. Having such a variety of flters Included in the case is an AC mains power supply, if you want to avoid stars trails. The range of objects and an off-axis guider with enough space to use available at one timevery makesaccurately for very fexible thermal noise USB cable, cable, a set of Allen a 2-inch ‘G’choose in WSG stands and were very with a standard coma ST4 corrector, feld fattener or keys, imaging as it is easy to the right flterfor forguider – the camera has a focal reducer is one of these good ideas. the celestial object at hand. impressed with nosepiece adaptor and a CD. Plug-ins for MaxIm DL, built-in off-axis guider installed in front of the flter The camera is supplied in a high-quality Peli Deep-sky requiresThis long exposures, so the sensitivity CCDSoft and AstroArt are included on the CD, imagingwheel. very convenient arrangement ensures > 1400 case, giving the contents excellent protection. it is imperative to ensure that your mount tracks and lack of Included in the case is an AC mains power supply, very accurately if you want to avoid stars trails. The thermal noise USB cable, ST4 cable, a set of Allen keys, a 2-inch ‘G’ in WSG stands for guider – the camera has a nosepiece adaptor and a CD. Plug-ins for MaxIm DL, built-in off-axis guider installed in front of the flter CCDSoft and AstroArt are included on the CD, wheel. This very convenient arrangement ensures >

CCD camera

Tried & tested

A built-in filter wheel and off-axis guider make for a neat package

QSI 683

WSG-8

A CCD camera

A built-in filter wheel and off-axis guider make for a neat manufacturing package Quality

www.thesecretstudio.net x 4, steve richards x 2

www.thesecretstudio.net x 4, steve richards x 2

A

owner’s observations

than my colour camera and this mismatch Name Steve Richards reduced the size of my fnished images too location Nr Wiston, West Sussex much. The larger sensor in the QSI 683 Equipment QSI 683 WSG-8 WSG-8 (17.96x13.52mm) allows me to Owner since June 2013 than my colour camera and this mismatch Name Steve Richards captureimages muchtoo better matched images at reduced the size of my fnished location Nr Wiston, West Sussex a far higher resolution. I bought the QSI 683 WSG-8 mono CCD much. The larger sensor in the QSI 683 Equipment QSI 683 WSG-8 WSG-8 me to Owner since camera June 2013specifcally for use on my Even though the QSI 683 WSG-8’s dual(17.96x13.52mm) allows capture much better matched images at KAF-8300 sensor was much larger, I was still imaging system. I use a mono CCD camera a far higher resolution. I bought the QSI 683 WSG-8 mono CCD able to use my existing set of 1.25-inch flters, on one telescope and a one-shot colour Even though the QSI 683 WSG-8’s camera specifcally for use on my dual which wasI was a real CCD camera a second KAF-8300 sensor was much larger, still advantage in terms of cost. imaging system. I use a monoon CCD camera telescope, use my existing set of 1.25-inch on one telescope andallows a one-shot Such was theflters, quality of the data captured by which me colour to capture twoable setstoof which was a real advantage in terms of cost.that it wasn’t long before CCD cameradata on a second telescope, that I can combine the new camera simultaneously Such was the quality of the data captured by which allows me to capture two sets of I started concentrating on using just this later on. My original mono CCD camera the new camera that it wasn’t long before data simultaneously that I can combine camera forthis most of my imaging. had a much smaller sensor (8.98x6.71mm) I started concentrating on using just later on. My original mono CCD camera

owner’s observations

had a much smaller sensor (8.98x6.71mm)



camera for most of my imaging.

tried & tested april 107

tried & tested april 107

KAF-8300 SenSor The KAF-8300 sensor conveniently bridges the gap between the typically affordable but smaller Sony sensors and their larger and much more expensive APS C or large format counterparts. With 8.3 megapixels across its surface and generous size (5.4μm) pixels, you can capture wide high-resolution images without sacrifcing sensitivity.

KAF-8300 SenSor

BuIlT-In oFF-AxIS GuIDer

TWo-STAGe PelTIer CoolInG The camera uses a two-stage Peltier thermoelectric cooling system with two internal fans and set point cooling to reduce image noise caused by heat from the sensor during long exposures. This system is capable of cooling the sensor down to 45°C below the ambient temperature.

TWo-STAGe PelTIer CoolInG SmAll DePTh

The camera uses a two-stage Peltier thermoelectric cooling Although the camera incorporates both flter system with two internal fans and set point cooling to a reduce wheel and anbyoff-axis guider, its total image noise caused heat from the sensor duringdepth long exposures. This front systemmounting is capable plate of cooling the sensor sensor down from the to the to 45°C below the ambient temperature.

The KAF-8300 sensor conveniently bridges the gap between the typically affordable but An autoguiding system is vital for accurate tracking smaller Sony sensors and their larger and during long-exposure imaging; much more expensive APS C or large formatthe most accurate way to do this with an off-axis guider and guide camera. counterparts. Withis8.3 megapixels across its surface The and generous size (5.4μm) pixels, you QSI 683 WSG-8 has a neatly installed off-axis can capture wide high-resolution images guider in front of the flter wheel, ensuring that only without sacrifcing sensitivity.

unfltered light reaches the guide camera.

BuIlT-In oFF-AxIS GuIDer An autoguiding system is vital for accurate tracking during long-exposure imaging; the most accurate way to do this is with an off-axis guider and guide camera. The QSI 683 WSG-8 has a neatly installed off-axis guider in front of the flter wheel, ensuring that only unfltered light reaches the guide camera.

is only 50.2mm. This means that a simple 6mm T-extension tube will make the camera SmAll DePTh compatible with the industry standard sensor to Although the camera incorporates both a flter focal reducer-feld fattener distance of 56mm. wheel and an off-axis guider, its total depth from the front mounting plate to the sensor is only 50.2mm. This means that a simple 6mm T-extension tube will make the camera compatible with the industry standard sensor to focal reducer-feld fattener distance of 56mm.



108 tried & tested april

Tried & tested BuIlT-In FIlTer Wheel Despite the camera’s relatively large sensor, it only requires 1.25-inch flters. Up to eight of these can be installed in the built-in flter wheel at a time. Because the flter wheel is integrated into the camera, only one 108 tried & tested april power cable and one USB cable are required, which cuts down on the usual tangle of wires.

Tried & tested Sky SayS…

> that the use of flters

Now add these: has no effect on the light BuIlT-In FIlTer Wheel 1. Starlight Xpress Lodestar autoguider

falling on the guide

Despite the camera’s relatively large sensor, it only ensuring requires 1.25-inch flters. Up to eight ofcamera, these can thus be installed in the built-in flter wheel at a the time.greatest Because chance of the flter wheel is integrated into the camera, only one fndingwhich a suitable guide power cable and one USB cable are required, cuts down on the usual tangle of wires.star even with very short

2. QSI EOS lens adaptor

exposures. An off-axis guider uses a small 3. SayS… QSI C mount> that thepick-off Sky prism, placed use of flters Now add these: has no effect on the light just outside the cone lens adaptor falling on the guide of light falling on the 1. Starlight camera, thus ensuring imaging sensor, to Xpress Lodestar the greatest chance of autoguider fnding adivert suitablelight guidefrom a test star to the camera for very analysis even with short of 2. QSI EOS lensguidestar exposures. An off-axismount unwanted movement and subsequent adaptor guider uses a smallThis provides correction under software control. 3. QSI C mount pick-off prism, placed a very accurate method of autoguiding. just outside the cone lens adaptor The short turret on top of the on camera’s casing of light falling the imaging sensor, to making it is machined with a male C-thread, divertguide light from a compatible with various cameras. Adjustment test star to the guide camera for analysis of of the guide camera’s focus was very simply unwanted movement and subsequent mount carriedunder out by slackening single grub screw correction software control.a This provides using one of the supplied Allen keys and rotating a very accurate method of autoguiding. The top of the the short focusturret ringon around itscamera’s thread.casing is machined with a malesensor C-thread, it The KAF-8300 is amaking ‘full frame’ chip, compatible with various guide cameras. Adjustment which means that unlike many sensors used of the guide camera’s focus was very simply in astronomical CCD cameras it requires a carried out by slackening a single grub screw mechanical shutter,Allen andkeys the and onerotating used in the using one of the supplied theQSI focus ring around its thread. 683 WSG-8 operates quietly and smoothly. The a ‘full frame’ chip,the camera and We KAF-8300 imaged asensor rangeisof objects with which means that unlike many sensors used were very impressed with its sensitivity and lack in astronomical CCD cameras it requires a of thermal noise mechanical shutter, andduring the oneexposures used in the of up to QSI WSG-8 operates quietly and smoothly. 20683 minutes. We would thoroughly recommend Wethe imaged range of objects the camera and QSIa683 WSG-8 to with intermediate or advanced were very impressed with its sensitivity and lack astrophotographers looking to upgrade to an of thermal noise during exposures of up to camera, flter wheel and 20all-in-one minutes. Wemono would thoroughly recommend S guidertoimaging solution. theoff-axis QSI 683 WSG-8 intermediate or advanced astrophotographers looking to upgrade to an all-in-one mono camera, flter wheel and off-axis guider imaging solution. S

Verdict

Build aNd dESigN

Build aNd dESigN EaSE Of uSE CONNECTiViTy fEaTurES EaSE Of uSE imagiNg QualiTy fEaTurES imagiNg QualiTy OVErall OVErall

steve richards x 3

steve richards x 3

Verdict CONNECTiViTy



★★★★★ ★★★★★ ★★★★★ ★★★★★ ★★★★★ ★★★★★ ★★★★★ ★★★★★ ★★★★★ ★★★★★ ★★★★★ ★★★★★

Our composite shot of NgC 6888, comprised of seven 600-second frames: fve in Ha and two in Oiii

Our composite shot of NgC 6888, comprised of seven 600-second frames: fve in Ha and two in Oiii

The Cygnus loop in Ha; the large flter wheel makes it easy to pick the right wavelength for the job The Cygnus loop in Ha; the large flter wheel makes it easy to pick the right wavelength for the job

110

Books

110

New astronomy and space titles reviewed

Books Lucky Planet David Waltham Icon £14.99  PB

New astronomy and space titles reviewed Earth is exceptional. It is a planet that has

RATINGS ★★★★★ Outstanding ★★★★★ Good ★★★★★ Average ★★★★★ Poor ★★★★★ Avoid You can order these books from our shop by calling 01803 865913

RATINGS ★★★★★ Outstanding ★★★★★ Good ★★★★★ Average ★★★★★ Poor ★★★★★ Avoid

Two minuTes wiTh DaviD walTham What inspired you to

You can order these books from our write the book? shop by calling 01803 865913 Ten years ago it occurred

to me that the simple question ‘Is Earth an endured around four billion years of good unusual planet?’ brought my passions of weather, purely by chance – the luckiest astronomy and geology together. We planet in the visible Universe. Twocan’t minuTes understand Earth properly without This is the argument of Lucky Planet, wiTh DaviD answering this question and we can’t do David Waltham written by University of London geophysicist walTham that without looking at how our world fts Icon David Waltham. Many scientists dismiss What inspired you to £14.99  PB intobook? the wider Universe. the idea that Earth is special; they favour write the Ten years ago it occurred suggestions ourIthome is actually Earth is exceptional. is a planet that has mediocre to me that the simple question Earth life an has evolved elsewhere? Do you‘Isthink endured around billion years of good on climatology and ice ages, and then and that lifefour is widespread throughout unusual planet?’ brought my passions of weather, purely by chance the luckiest Defnitely. The basic idea behind Lucky moves abruptly on to the idea of music, the Universe. As the–title suggests, astronomy and geology together. We planet in the visible Universe. is without that the Universe is so large that later linking this with planetary orbits. EarthPlanet Waltham disagrees, detailing the many can’t understand properly This is the argument of Lucky Planet, even very odd answeringbe thisbest question and we can’t doplaces like Earth are Some of the chapters could perhaps waysbyinUniversity which Earth hasgeophysicist just been very written of London without looking atinevitable. how our world fts Earth is so rare that we’re I think expressed via a timeline, that as embedding David Waltham. Many scientists dismiss fortunate indeed. into the wider Universe. the idea that Earth is special; they favour unlikely to ever fnd another world with a copious details about It is a refreshing angle amid suggestions our home is actually mediocre biosphere as complex as ours; the fip side atmosphere, temperature numerous similar titles Do you think life has evolved elsewhere? on climatology and ice ages, and then and that life is widespread throughout of this argument and feedback processes Defnitely. The basic idea behind Lucky is that there are probably moves abruptly on to the idea of music, thetouting Universe.the As opposing the title suggests, many such places at various stages in Planet is that the Universe is so large that scattered across the view. Waltham explores later linking this with planetary orbits. Waltham disagrees, detailing the many even very odd places like Earth are Some of the chapters could perhaps beEarth’s best ways which Earth has just been very Universe. It’s just that they are so far apart history into theinvarious properties I think Earththey is so are rare that we’reisolated from each other. expressed via a timeline, as embedding fortunate indeed. forever dense inevitable. paragraphs our planet possesses unlikely to ever fnd another world with a copious details about It is a refreshing angle amid of textbiosphere is quite as complex as ours; the fip side that have led to atmosphere, temperature numerous similar titles diffcult to argument digest. is thatWhat its habitability, makes a planet ‘lucky’? of this there are probably and feedback processes touting the opposing Lucky covering astronomy, many such places scattered It’s notacross that the any single property is rare; it’s at various stages in Although view. Waltham explores Universe. It’s just that they are so far apart of many slightly unusual Earth’s history into thebiology, various properties Planet contains cosmology, the combination they are forever isolated from each other. dense paragraphs ourclimatology, planet possesses several brilliant properties. If one in 10 planets are the of text is quite that have led to analogiesWhat and makes a planetright and geology. size and one in 10 planets orbit at diffcult to digest. its habitability, ‘lucky’? explanations, at times it The most interesting the right Although Lucky covering astronomy, It’s not that any single property isdistance rare; it’s and one in 10 planets Planet contains biology, cosmology, consideration is obvious thatthe Waltham is of many and important combination slightly unusual have the right amount of water… you can several brilliant climatology, properties. If one in 10 planets are the a scientist frst and an author is that in order for Earth to be Minute changes could see where I’m going with this. analogies and and geology. size and one have rendered Earth second, as there isright a tendency to in 10 planets orbit at how it is now, our planet must explanations, at times it The most interesting the right distance and one in 10 planets a very different place cram in technical information have been potentially What do you think about the latest is obvious that Waltham is and important consideration habitable have the right amount of water… you can the expense However, for ainvery portion history. exoplanet searches? scientist frst and of an readability. author is that orderlarge for Earth to be of its Minute changes could a at see where I’mifgoing with this. have it rendered Earth second, as there is a tendency how it is now, planet must you wish to learn abouttothe climatology of While thisour may seem obvious, is actually Despite all I’ve said, I’m a huge supporter a very different place cram technical information have beenan potentially habitable do present you think about theongoing latest our in planet from its formationWhat to the quite intriguing perspective – if the of the hunt for exoplanets. I think at the expense of readability. However, if for a very large portion of its history. exoplanet searches? day, it serves as a comprehensive overview. Earth had had slightly more changeable the data we have at present points to While this may seem obvious, it is actually you wish to learn about the climatology of Despite all I’ve said, I’m a huge supporter weather or a marginally different ★★★★★ habitable our planet from its formation to the present of the ongoing hunt for quite an intriguing perspective – if the exoplanets.worlds I think being rare, but that’s atmospheric composition at any one day, it serves as a comprehensive overview. Earth had had slightly more changeable the data we have at present to little data. What we need basedpoints on very weather marginally ★★★★★ NICkY GUTTrIDGE is a science habitable worlds beingis rare, butinformation, that’s point,orita would be different an entirely different journalist more which will hopefully atmospheric composition at any one based on very little data. What we need planet today. and Hubble public information offcer prove my pessimism to be misplaced. point, it would be an entirely different NICkY GUTTrIDGE is a science journalist is more information, which will hopefully When it comes to structure, however, planet today. and Hubble public information offcer prove my pessimism to be misplaced. Dr DavID WalTham is a lecturer in the book is atolittle unusual. For example, When it comes structure, however, reader price £13.99, subscriber price £12.99 Dr DavID WalThammathematical is a lecturer in geology at Royal Holloway theWaltham book is a little unusual. focuses for For an example, oddly long time P&P £1.99 Code: S0414/2 reader price £13.99, subscriber price £12.99

Lucky Planet

Waltham focuses for an oddly long time



P&P £1.99 Code: S0414/2

mathematical geology at Royal Holloway

books APRIL 111

Observing by Hand

19th century, images were produced by hand, requiring artistic skill, an understanding of the heavens and an ability to record detail accurately and quickly. The style of Sketching the Nebulae The Terrestrial Life writing refects the content, being careful and meticulous, just as the observers were in the 19th Century and Times of Sir who produced the images discussed. Bernard Lovell Each chapter focuses on different Omar W Nasim oF The astronomers and how their approach to Chicago John Bromley-Davenport m on T h APRIL 111 drawing nebulae adds to the bigger story. books £31.50  hB Bene Factum Publishing Through the work of Lord Rosse and his £20  hB assistants John Herschel, EP Mason, William As befts its subject 19th century, images were produced by hand, Lassell and Wilhelm Tempel, we see the Sir Bernard lovell was matter, Observing by requiring artistic skill, an understanding range of techniques used, and the factors Hand looks beautiful. one of the most eminent of the heavens and an ability to record Space thatand shaped them. In doing so, Nasim Has No Frontier British scientists of the It deals with the detail accurately quickly. The style of Sketching the Nebulae TheinTerrestrial Life the content, careful played shows us the being role theory shaping tricky, rather writing refects past hundred years. and meticulous, just as the observers were in the 19th Centuryunder-researched what each astronomer saw, the skill and Times of Sir a pioneer of radar who produced the images discussed. involved in ‘translating’ thatBernard onto paper,Lovell area of observational book techniques, originator Each chapter focuses on different Omar W Nasim o F T and the fuidity of the border between art astronomy, that h eof Jodrell Bank astronomers and how their approach to Chicago John Bromley-Davenport m o n T h and adds science. anyone an Factum interestPublishing place betweendrawing nebulae to theFor bigger story. with £31.50  hB Bene Observatory and a popular orator of the workappreciation of Lord Rosse and his beauty £20of  nebulae, hB of the observation and publication. AuthorThrough Omar theand physical sciences, his legacy is immense. Herschel, EP Mason, William As befts its subject this is a book that will leave you thinking. Nasim uses tools from art history asassistants well John This biography by family friend John Lassell and Wilhelm Tempel, we see the Sir Bernard lovell was matter, Observing by as a good understanding of astronomy to ★★★★★ coming little more than Hand looks beautiful. range of techniques used, and the factors one Bromley-Davenport, of the most eminent explore this complicated that shaped them. In doing so, Nasim It deals withrelationship the British scientists of the a year after lovell’s death, is an insightful roleEmIlY theory played in shaping is a writer and pastand rather hundred years.account of the astronomer’s between art andtricky, science; between theshows eye,us theDr WINTErBUrN detailed what each astronomer saw, the skill under-researched a pioneer of radar the mind and the hand; between what is visiting fellow at the University of Leeds life. Using carefully researched original area of observational involved in ‘translating’ that onto paper, techniques, originator observed and the image produced. and the fuidity of the border between art astronomy, that of documents, Jodrell Bank and peppered with personal Today astronomy is intertwined with reader price £27.99, subscriber price £26.99 anecdotes and science. For anyone with an interest place between Observatory and a popular orator from of the lovell himself, BromleyP&P of £1.99 Code:ofS0414/4 photography. For a signifcant part of the and appreciation the beauty nebulae, observation and publication. Author Omar physical sciences, his legacy is immense. Davenport gives a fascinating profle of this is a book that will leave you thinking. Nasim uses tools from art history as well This biography by family friend John the man, his science, his beliefs, and his as a good understanding of astronomy to ★★★★★ Bromley-Davenport, coming little more than trials and tribulations. explore this complicated relationship a year after lovell’s death, is an insightful although many of the basic details of between art and science; between the eye, Dr EmIlY WINTErBUrN is a writer and and detailed account of the astronomer’s the mind and the hand; between what is visiting fellow at the University of Leeds lovell’s life are available elsewhere, this life. Using carefully researched original observed and the image produced. the book concerns itself withdocuments, topics and peppered with personal offering digs a little deeper into some of Today astronomy is intertwined with reader price £27.99, subscriber price £26.99 of greater interest to astronomers andfrom lovell the anecdotes himself, Bromleymajor events of his life. The account P&P £1.99 Code: S0414/4 photography. For a signifcant part of the Davenport gives a fascinating profle of space fans. How easy is it really to travel of beliefs, lovell’sand wartime radar development is the man, his science, his his vast distances in space, for instance? excellent, flling in hitherto unpublished trials and tribulations. What propulsion systems could be used? Charles l adler although many of the basic details of details. The stresses and strains during the What are the practicalities oflovell’s founding Princeton life are available elsewhere, this design and construction of the 76m radio the book concerns itselfand withterraforming topics colonies planets? £19.95  PB offering digs a little deeper into some of telescope at Jodrell Bank that bears lovell’s of greater interest to astronomers and the light? major events of his life. The account Will we ever travel faster than space fans. How easy is it really to travel name are ably portrayed. lovell’s of lovell’s What arefor theinstance? chances of fnding and wartime radar development is Fans of science-fction vast distances in space, involvement with certain secretive aspects excellent, flling in hitherto unpublished communicating with ET? details. The stresses and strains during the and fantasy talesWhat propulsion systems could be used? Charles l adler of the Cold War are well known, but this What are the practicalities founding Princeton These are of just a few of thedesign rangeand of construction of the 76m radio usually realise that account contains new facts based on colonies andtopics terraforming planets? £19.95  PB examined by author and professor they need to suspend telescope at Jodrell Bank that bears lovell’s recently released offcial records. Will we ever travel faster than light? Physics Charles Adler. Hename says are thisably is portrayed. lovell’s belief and allowWhat are theofchances of fnding and Fans of science-fction The assertion that lovell was duped by involvement the with bookET? he would have wanted to readwith certain secretive aspects some communicating and fantasy talespoetic licence a committed marxist into believing he of the Cold War are well known, but this These are just few of the range of but offers a word of usually realise thata story may as aa15-year-old boy, so that account contains new was facts based on an undercover government agent by author and professor they needbe to told. suspend warning: that readers shouldrecently have some Whiletopics examined released offcial records. seems both incongruous and speculative. of Physics Charles Adler. He says this is belief and allow knowledge of algebra and calculus; and that lovell was duped by a few authors The assertion the book he would have wanted to read some poetic licence So believing too is the a committed marxist into he inference that lovell himself indeed there are many formulae and try hard to keep as a 15-year-old boy, but offers a word of so that a story may was a spy. Nevertheless, this biography was an scattered throughout theundercover government agent warning: thatequations readers should have some be told. their Whilenarratives seems both incongruous speculative.and scholarly read. is aand fascinating knowledge ofbook. algebraDespite and calculus; a few this, and the writing style is within the bounds of authors scientifc possibility,

Space Has No Frontier

book

Observing by Hand

Wizards, Aliens and Starships

Wizards, Aliens and Starships

★★★★★ are many and try hard keep andformulae will give sci-f fanswas a rewarding others seem to make up to new laws of indeed therelight a spy. Nevertheless, this biography equations scattered throughout the their narratives and thought-provoking read.is a fascinating and scholarly read. physics as they go along. book. Despite this, the writing style is within the bounds of scientifc possibility, Dr alaSTaIr GUNN is a radio astronomer ★★★★★ Aliens andlaws Starships lookslight and will★★★★★ give sci-f fans a rewarding othersWizards, seem to make up new of at Jodrell Bank Observatory in Cheshire at many ofgo the common concepts and and thought-provoking read. physics as they along. Dr alaSTaIr GUNN is a radio astronomer Wizards, Aliensthat and Starships plot devices are usedlooks in science ★★★★★ PaUl SUThErlaND is a space writer at Jodrell Bank Observatory in Cheshire at many of the common concepts and reader price £18.99, subscriber price £17.99 fction and examines the actual science and journalist plot devices that are used in science PaUl SUThErlaND is a space writer P&P £1.99 Code: S0414/3 behind them. There’s a hefty reader price £18.99, subscriber price £17.99 fction and examines the actual sciencechunk and journalist £1.99 Code: S0414/3 dealing with theafantasy world of Harry behind them. There’s hefty chunk reader price £14.95, subscriberP&P price £13.95 dealing with worldfrom of Harry Potter tothe getfantasy past, but there on reader price £14.95, P&P £1.99 Code: S0414/1 subscriber price £13.95 So too is the inference that lovell himself

Potter to get past, but from there on

P&P £1.99 Code: S0414/1



112 GEAR APRIL

Gear

112 GEAR APRIL

Elizabeth Pearson rounds up the latest astronomical accessories

Gear 1

4

1 Orion Newtonian Visual Centering Device Price £139 • Supplier SCS Astro 0800 0181544 • www.scsastro.co.uk Designed for use with Newtonian refectors, this device allows you to centre your imaging target visually through its built-in eyepiece, rather than your camera’s screen or software.

Elizabeth Pearson rounds up the latest astronomical accessories

1

4

2 BaaderVisual Classic Q-Eyepiece Set 1 Orion Newtonian PriceDevice £215 • Supplier The Widescreen Centre Centering

020 7935 Price £139 • Supplier SCS2580 Astro • www.widescreen-centre.co.uk 0800 0181544 • www.scsastro.co.uk

The set includes four eyepieces, ranging from

Designed for use with 6mm toNewtonian 32mm, asrefectors, well Baader’s Q-Turret, which this device allows you to centre your imaging slots into a telescope and allows you to switch target visually through its built-in eyepiece, between all four with ease. The set comes with rather than your camera’s screen or software.

5

a 2.25x Barlow lens.

2 Baader Classic Q-Eyepiece Set

3 Lacerta Newtonian Carry Case

Price £215 • Supplier The Widescreen Centre 020 7935 2580 • www.widescreen-centre.co.uk

2

Price From £72

Supplier 365 Astronomy

• The set includes four eyepieces, ranging from 020 3384 5187 • www.365astronomy.com 6mm to 32mm, as well Baader’s Q-Turret, which slots into a telescope and to allows you to switch Designed transport and store Newtonian between all four with ease. The set comes with telescopes, this padded case helps keep your a 2.25x Barlow lens.

5

kit safe. Available in various sizes.

3 Lacerta Newtonian Carry Case

4 Celestron 9x50 Illuminated Right Angle Correct Image Designed to transport and store Newtonian Finderscope telescopes, this padded case helps keep your

Price From £72 • Supplier 365 Astronomy 020 3384 5187 • www.365astronomy.com

2

Pricein£112.99 • Supplier Harrison kit safe. Available various sizes.

Telescopes 01932 703605 • www.harrisontelescopes.co.uk

4 Celestron Illuminated This9x50 fnderscope uses a dual crosshair, so you Right Angle Correct Image can centre objects without obscuring them. Its Finderscope right-angled orientation makes it easy to use Price £112.99 • Supplier Harrison Telescopes even when your scope is pointing 01932 703605 • www.harrisontelescopes.co.uk

3 3

at the zenith.

This fnderscope uses a dual crosshair, so you can centre objects without obscuring them. Its right-angled orientation makes it easy to use even when your scope is pointing at the zenith.

5 SmarTouch Chunky Knit Touchscreen Gloves

Price £15 • Supplier Totes 01277 636802Knit • www.totes.co.uk 5 SmarTouch Chunky

6

Touchscreen Glovesmaterial in the fngertips promises Conductive Price £15 • Supplier Totesto carry to let you 01277 636802 • www.totes.co.uk

on using touchscreen devices during cold observing sessions without the Conductive material in the fngertips promises need to take your gloves off – smart indeed. to let you to carry on using touchscreen devices during cold observing sessions without the need to take your gloves off – smart indeed.

6 Lego Curiosity Rover Price £24.99 • Supplier Lego

6 Lego Curiosity Rover1111 • www.lego.com 00 800 5346 Price £24.99 • Supplier Lego the real Curiosity 00 800 5346Just 1111like • www.lego.com

rover, this Lego replica

is Curiosity capablerover, of tackling a variety of terrains Just like the real this Lego replica is capable of thanks tackling a of terrains suspension system. tovariety its rocker-bogie thanks to its rocker-bogie suspension system.



6

114 EXPERT inTERviEw APRIL

WHAT I REALLY WANT TO KNOW IS…

What is life like on the ISS? ESA astronaut Paolo Nespoli served as a fight engineer aboard the ISS from December 2010 to May 2011 114 EXPERT inTERviEw APRIL interviewed by eLiZAbetH PeArSOn

you, a terrestrial human being,TO KNOW IS… space – a place where there is no weight! WHAT I hen REALLY WANT go into space, you are faced with At 8pm we usually had a debriefng where we

W

What is life like on the ISS?

the fact you are in a new could talk about what happened during the environment. You’re day and get feedback. After that we had there to work, and you want to work, an hour and a half before we went to ESA astronaut Paolo Nespoli served as a fight engineer but frst of all you need to adapt sleep at 10pm, and could do yourself. You fnd yourself whatever we wanted. aboard the ISS from December 2010 to May 2011 in a new place where there is I spent most of my time interviewed no gravity, and you havebytoeLiZAbetH PeArSOn going through emails and learn everything from talking with my family. hen you, a terrestrial human being, space – a place where there is no weight! scratch. Yougoneed to into space, you are faced with At 8pm we usually had a debriefng where we The International Space become an the fact you are in a new could talk about what happened during the Station is a confned, environment. day and get feedback. After that we had isolated place and I was extraterrestrial person.You’re there to work, and you want to work, an hour and a half before we went to grateful that there was It can be extremely but frst of all you need to adapt sleep at 10pm, and could do frustrating, but it is a way to communicate. yourself. You fnd yourself whatever we wanted. bit is Ground control realises in also a newvery placenice, whereathere I spent most of my time being little that you are a human nolike gravity, andayou havekid to going through emails and learn everything from talking with my family. discovering new things. being, not a machine, scratch. Youdays need to The International Space and they come up with all Most followed the become an Station is a confned, same routine. At 6am you sorts of tricks to make it extraterrestrial person. isolated place and I was wake up, have breakfast, It can be extremely grateful that there wasmore bearable. One of them frustrating, it isdo whatever you a way to communicate. clean upbut and is to make sure each also very nice, a bit Ground control realises need to be ready to start work of the astronauts has their own like being a little kid that you are a human at 7.30am. phone. You need to pay attention discovering new things. being, not a machine, Wedays spent about and check Most followed theeight hours doing and they come up with all the availability of the scheduled work. If we had a shuttle satellite it transmits through, but once same routine. At 6am you sorts of tricks to make it wake up, haveorbreakfast, more bearable. One of them arriving a space walk to complete there you learn how to use it it’s just like any other clean up and whatever isphone. to makeIsure eachcall people to say hello and would bedo a lot to doyou to prepare, but most of that would need to be ready to start work of the astronauts has their own time we were taking care of the station or carrying I talked to my wife every day to let her know what Nepsoli, right, was a at 7.30am. phone. You need to pay attention out scientifc experiments. was going on up there. prolifc photographer, We spent about eight hours doing and check the availability of the taking 26,000 images satellite it transmits One of through, things Ibut would scheduled work. If we had a shuttle once do every day was go arriving or a space walk to complete there you learn howinto to use it it’s just like any other the cupola, a room with 360° views out into would be a lot to do to prepare, but most of that phone. I would call people to say hello and space, and just look at Earth as we passed by. Running experiments could be psychologically time we were taking care of the station or carrying I talked to my wife every day to let her know what Nepsoli, right, was a I took something like 26,000 pictures while I was had to train for so many things that we outtaxing. scientifcWe experiments. was going on up there. prolifc photographer, in space. Atday frst might have learnt how to carry out a particular taking 26,000 images One of things I would do every wasit’s go not easy; in the beginning into the cupola, a room withseen 360° from views out intois just this blue ball. But Aexperiment lot of hard work Earth space a year beforehand. A couple of times space, and just look at as we passed Running could be and psychologically asEarth you become anby. extraterrestrial person, you I wentexperiments to do something I had no idea I had I took something like 26,000 pictures while I was taxing. We had to train for so many things that we develop this eye. You can just glimpse down even trained for that experiment. Some were very in space. At frst it’s not easy; in the beginning might have learnt how to carry out a particular and youthis know where repetitive and I was always sleep deprived, so Earth seen from space is just blue ball. Butyou are. experiment a year beforehand. A couple of times I hope this experience is something that sometimes I fell asleep! The as you become an extraterrestrial person, you I went to do something and I had no scientists idea I had were develop this eye. Youmany can just glimpsewill down even trained for my that response experiment. Someinwere very people be able to do in the future. measuring time milliseconds, but and you know whereYou you are. repetitive and I was always so I’d feel stupid. learn a lot about yourself, about other I was napping. Whensleep thatdeprived, happened, I hope this experience is something that sometimes I fell asleep! The scientists were people and about Earth. Seeing our planet One thing that helped was doing exercise – I could many people will be able to do in the future. measuring my response time in milliseconds, but upabout thereother gives you a perspective and switch off When and think about other things. You learn a lot aboutfrom yourself, I was napping. that happened, I’d feel stupid. It is very About PAoLo NESPoLI understanding that is very different from important to keep your body up to par and lower people and about Earth. Seeing our planet One thing that helped was doing exercise – I could Paolo Nespoli served as a from up there gives you a perspective and switch off and think about other things. It is very any you can get from the ground – I wish everybody the negative effects of microgravity, but exercising About PAoLofight NESPoLI engineer aboard thethat is very different from understanding important to keep your body up to par and lower could share that. Now that I’m back down on was also very relaxing. Two hours every dayPaolo wereNespoli served as a ISS as part of anyExpeditions you can get from the ground – I wish everybody the negative effects of microgravity, but exercising fight engineer aboard the the planet, though, spent on physical ftness. is awere special treadmill 26 and 27. He frstshare travelled could that. Now that I’m back down onI like to say that I am still was also very relaxing. Two hoursThere every day ISS as part of Expeditions guyI that grew up in a small town in as well as a machine called the Advanced the planet, though, Ithe like same to say that am still spent on physical ftness. There is a special treadmill Resistive to travelled space aboard Space 26 and 27. He frst the same guy that grew in a small in as Exercise well as a machine called the Advanced Resistive S theupmiddle of town nowhere. Device, which lets you do weightlifting in aboardShuttle in 2007. to space Space Discovery

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Exercise Device, which lets you do weightlifting in



Shuttle Discovery in 2007.

the middle of nowhere. S

SoUtHern HeMiSPHere in aPril With Glenn Dawes

00:00 23:00 22:00

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The chart accurately matches the sky on the dates and times shown. The sky is different at other times as stars crossing it set four minutes earlier each night. We’ve drawn the chart for latitude –35° south.

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A total lunar eclipse will be visible from Leo is one of the few constellations SoUtHern HeMiSPHere aPril eastern Australia on 15 April. Midthat looks likein its namesake – but only eclipse is aroundWith moonrise in the evening Glenn Dawes from the northern hemisphere. From down twilight: a good WHen time to observe would be just under the Lion sits low in the north, but upside to USe tHiS cHart > 1 April before totality ends at 18:24 EST. From central down. Itsshown. head and shoulders are 00:00 referred to The chart accurately matches the sky on the dates and times > 15 April 23:00 The sky is different at other times as stars crossing it set four minutes Australia totality ends before moonrise, with as the Sickle, with its top member Leo’s > 30 April 22:00 earlier each night. We’ve drawn the chart for latitude –35° south. Western Australia missing all of the eclipse. brightest star, mag. +1.4 Regulus (Alpha (α) The afternoon of 29 April brings an annular Leonis). To the east lie its hindquarters, aPril eclipseHigHligHtS of the Sun with partial phasesStarS visible and conStellationS consisting of a conspicuous triangle of stars. across Australia. Maximum eclipse This group’s brightest star is mag. +2.1 A total lunar eclipse will be visible from is Leo is one of the few constellations eastern Australia on 15 April. Midaround 17:00 EST from the eastern states that looks like its namesake – but only its name is short Denebola (Beta (β) Leonis): eclipse around moonrise the evening from the northern hemisphere. From down andis15:00 EST from in Western Australia. for an Arabic phrase meaning ‘tail of the Lion’.

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Sky at Night - April 2014

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