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The bimonthly magazine of the Society for Popular Astronomy
November-December 2013
PA_2013-1112 Adlard:PA_2013-1112.qxd 29/10/2013 17:24 Page 1
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• The UK’s best astronomy magazine • The latest news in astronomy and space• Britain’s best monthly guide to the night sky• Unique articles that bring astronomy to life• The latest telescopes, books and gadgets reviewed
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COMETOF THECENTURY?What the experts say
about comet ISON
Leaving the Solar System
Curiosity’s year on Mars
Complete night sky guideVoyager heads into the unknown
The NASA rover’s story so far
All you need to know about what’s up this month
01_Cover_SeptFIN.indd 1
05/08/2013 17:06
Subscribe today and get a free copy of Hubble Reborn,
usually priced £8.99! (Offer available to SPA members
only, while stock lasts. Offer expires 30 November 2013)
Save£12*
HUBBLEREBORNThe Story of the Space Telescope
By Emily Baldwin and Keith Cooper
HU
BB
LE REB
OR
N: TH
E STOR
Y OF TH
E SPACE TELESCO
PE
Emily B
aldw
in an
d Keith
Cooper
P
ole Star Pu
blication
s
[01] Hubble CoverFIN.indd 1 27/11/09 11:56:47
SPECIAL SUBSCRIPTION OFFER FOR SPA MEMBERS
FREEHubble Reborn
A 100-page bookazine featuring dozens of
spectacular images from the world-famous space
telescope, as well as Hubble's story from construction to
launch and the daring space missions to repair it.
THE GREATEST GALAXY IN THE SKYYour guide to observing Andromeda
Measuring the stars
Pluto on the horizon
Deep sky mega mosaics
Europe’s new mega-mission
Unmasking the mysteries of an icy world
Processing the professionals’ imagesOctober 2013 £3.99
Mars meetsComet ISON
00_Cover_Oct13.indd 1
09/09/2013 20:45
SPA Subs Ad Oct13.indd 85 16/09/2013 10:31
4 Past Pages Peter GregoBetter late or never?
5 AstroNewsPlanets around other stars
Meteorites and impacts
Kepler’s new slant on exoplanets / Peter Higgs awarded Nobel Prize
10 Telescope Topics Ian MorisonObserving the Sun in the light of H-alpha, 2: Drawing and imaging the Sun in H-alpha
12 Amateur Scene Peter WadeMemories of working alongside Sir Patrick
Cloudy nights can be lively nights
Out and about / Fight night blight, get light right
Explosive start for northwest rocketeers / Host societies welcome BAA
24 Space Exploration Helen WalkerMars news roundup:
India’s first mission to the Red Planet
Hebe Chasma—a Martian supervolcano?
Methane mystery / water success
ISS activities / Near-drowning in space / Penetrator
27 Young Stargazers George Ford / Ezzie PearsonFamous astronomers: John Goodricke David Scanlan
A partial eclipse of the midnight Sun Simon Cran-McGreehin
Help! I don’t understand ... Dark matter Robin Scagell
What’s it like to work at the European Space Agency? Emily Baldwin
32 ReviewsThe Cambridge Photographic Moon Atlas / Astronomy Diary
The Clementine Atlas of the Moon
34 LettersThe Seeliger Effect—on Earth as it is on Saturn?
Nova Del 2013 / New brush sweeps cleaner
36 Section ReportsOdd flash probably no point meteor / View a scene of crater catastrophe
Northern graze
Saturn, the only game in town
Cheeseburger on chips
Will C/2012 S1 (ISON) be the comet of the century?
41 The Society PagesWonderful weekend in Belfast Paul Sutherland
Astronomer Royal addresses successful SPA Convention
Come to the SPA meeting on 25 January 2014 / Explore the Universe in Cardiff
SPA statement on threat to The Sky at Night Robin Scagell
SPA meetings to come
44 Sky Diary Peter GregoLunar occultations Mell Jeffrey
Meteor notes Tony Markham
46 SPA contacts
47 Showcase Peter GregoMembers’ images of ‘celestial rings’
FeaturesProduction
November-December 2013Volume 60Number 6
www.popastro.com
Editor / design and layout
Peter Grego
7 Parc-An-Bre Drive
St Dennis
St Austell PL26 8AS
Advertising Manager
Peter Grego
Distribution Manager
Barry Turvey
36 Fairway
Keyworth
Nottingham NG12 5DU
Printers
Adlard Print
The Old School
Ruddington
Nottingham NG11 6HH
PA welcomes articles on all aspects of
astronomy. Opinions expressed in PA
are not necessarily those of the SPA.
The SPA can’t be held responsible for
the accuracy of descriptive statements
or for the quality of goods advertised.
ISSN: 0261-0892
© 2013 The Society for Popular
Astronomy. Popular Astronomy is
published bimonthly for SPA members.
Annual subscription: £18. For details
about the SPA and how to join, visit:
Regulars
Cover: This combined infrared/X-rayimage of the Andromeda Galaxy (atcentre) was taken by two ESA spaceobservatories—Herschel and XMM-
Newton. Herschel finished itsmission in April 2013, but its
observations will occupy scientistsfor a long time. Images surrounding
are (clockwise from top left):infrared, X-rays, composite and
optical. See Young Stargazers forEmily Baldwin’s account of working
for ESA. Image: ESA.
9 Healing stars Paul Greenewich
16 The Goldilocks Zone, refined Tony Auffret
19 Mars, before the Space Age Professor Barrie W. Jones
PopularAstronomy
November-December 2013 www.popastro.com Popular Astronomy p3
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JOHN Lytheer’s editorial comments in
Hermes (Oct-Dec 1963) consisted
entirely of an impassioned call for the
urgent establishment of a ‘National
Centre’ for UK astronomy.
‘In America, Russia and some other
countries, interest in astronomy is
carefully fostered,’ he explained.
‘Planetaria, public observatories,
sympathetic consideration of amateurs’
problems locally and positive
encouragement nationally are the order
of the day. [LOL—current editor]
‘In this country, radio and television
programmes have awakened the interest
of thousands, probably millions of
people. Thousands visit the Science
Museum and London Planetarium every
year. Hundreds attend astronomical
courses up and down the country. Great
national newspapers publish
astronomical information. Books
catering for every possible level of
knowledge or age pour in to shops and
libraries. The number of astronomical
groups and societies is growing apace.
More and more people are building their
own telescopes or seeking advice on
purchase.’
Lytheer went on to propose a large,
purpose-designed building set in country
north of London. ‘It would contain
lecture rooms, a planetarium and
demonstration facilities. Laid out partly
as a museum and partly as a display of
astronomical models, it would have a
number of first-class instruments, each
in its own dome complete with driving
mechanisms and the latest photographic
and electronic auxiliary equipment. It
would be completely equipped with radio
receivers able to pick up and record not
only natural radio emission from local
and distant space but also signals or
speech from orbiting satellites, probes or
manned space expeditions. In its
basement would be workshops where
mirrors could be ground and finished.
Lathes, machine tools and engineering
facilities for the construction of
mountings, would also be provided.
Testing shops, photographic dark-rooms,
a spectrographic laboratory and perhaps
even a small computer [:-) Ed] would be
included. Living accommodation would
be on hostel lines.’
‘At first glance it might seem insanely
impractical,’ he continued ‘but I believe
it could be achieved with the co-
operation of three Government
departments, the support of every
astronomical organisation, the
enthusiasm of every astronomer and
the goodwill of a number of
industrial companies’.
Lytheer bemoaned the lack of
vociferous activity among
astronomers and the absence of a
campaigning spirit among them,
accusing astronomers of ‘having little
fire in their bellies’ and of being
‘placid folk, content to work quietly
and in the dark’.
Lytheer’s Utopian vision of a one-
stop astronomy shop for the UK might
have sounded (and still does sound)
suspiciously authoritarian rather than
insane. The obvious contradiction and
illogic in his editorial was that while
maintaining an urgent need for a
national centre for astronomy, he
painted a glowing picture of a boom-time
for UK astronomy in 1963, with interest
in the subject being amply catered for by
the media, publishing, museums,
planetaria, commerce, various groups
and societies. If all was going so well in
the UK, why the need, let alone the
urgent need of a national centre for
astronomy?
It’s impossible to tell whether society
members responded at all to Lytheer’s
editorial, as there’s only a single
published letter (on an unrelated
subject) in all the subsequent issues of
Hermes for at least three years!
No country has ever had (nor, I think,
ever will have) a national centre along
Lytheer's lines. Besides its unfeasibly
broad remit and the sheer cost of such a
project (presumably borne by the
taxpayer), there’s the uber-Herculean
task of amicably arriving at an all-
encompassing, top-down, Government-
sponsored, committee-bound solution
that meets the approval of all parties
concerned. Then there’s the unfairness of
its single geographical location and the
perpetual political machinations that
would grind away behind (and
sometimes in front of) the scenes.
Lytheer’s vision is a ‘better never’ idea.
However, the modern entity nearest to
Lytheer’s proposal is Leicester’s National
Space Centre, which opened in June
2001. It has become the UK’s largest
visitor attraction dedicated to space and
space exploration and welcomes around
a quarter of a million visitors each year.
Originally the idea of the University of
Leicester, it was supported by Leicester
City Council and won a joint bid to the
Millennium Commission. Although far
from being a complete one-stop space
‘shop’ for astronomers, it does have a
very wide scope that successfully
conveys education, inspiration and
visual entertainment about space-related
subjects to the public. SPA members
even get a discounted entry fee—see
www.spacecentre.co.uk for more details
and www.popastro.com/discounts to find
more places in the SPA discount scheme.
In Popular Astronomy, (Oct-Dec 1988)
editor Ian Ridpath headlines the happy
news Merger saves Schmidt. He writes:
‘The UK Schmidt Telescope in
Australia has been saved from the
threat of closure by merging it with the
Anglo-Australian Observatory ... For the
past three years the Schmidt telescope
has been threatened with cut-backs or
even closure because of lack of money for
astronomy in the UK. Australian
astronomers saved the telescope by
offering to share the costs of running it.
The UK and Australia already
contribute equally to running the AAT...’
Ironically, this happened at a time of
UK economic prosperity. But, better late
than never, saving the UKST proved a
great decision. The 1.2-m telescope, now
operated by the Australian Astronomical
Observatory, lies near the 3.9-m AAT at
Siding Spring. Its worth is proven; the
main source of southern optical survey
data, its images created the Guide Star
Catalog for the Hubble Space Telescope
and the Digitized Sky Survey. It’s now
used and funded by RAVE (RAdial
Velocity Experiment)an international
project to measure a million stars.
Our human desire to understand the
Universe never ends. Sadly, science has
long been starving (not just hungry) for
taxpayer funding. The benefits of
knowledge (including boosting the
economy) are incalculable in the long
run. Further cuts simply expand fat cats,
impoverishes the people and steepens
the downward curve of UK excellence.
So, Mr Cameron: Increase funding now!
Better late than never.
Better late or never?
PETER GREGO looks at thecontents of this magazine50 and 25 years ago
Hermes (1963)
and PA (1988),
Oct-Dec issues.
Past Pages
p4 Popular Astronomy www.popastro.com November-December 2013
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THE infrared Spitzer Space
Telescope and the Hubble
Space Telescope (HST) have been
studying one of the nearest
exoplanets, HD189733b, and have
come to a rather startling
conclusion that it would look like a
deep blue dot if we could resolve it.
HST observed the exoplanet
disappearing behind the star and
found that the level of blue light
dropped, but the red and green
were constant, showing that this is
a blue planet. However the deep
blue colour is the result of tiny
glass beads in the atmosphere and
not oceans of liquid water.
Spitzer showed that the
temperature on the sunny side of
the planet is 1000°C and on the
night side 750°C, so there are very
strong winds racing round from
one side of the planet to the other,
creating hazy clouds full of small
glassy particles.
Data from the Kepler satellite,
focused on the Cygnus region in
the Milky Way, is continuing to
show interesting exoplanets. One
recent discovery by Kepler is a set
of planets around a K2V star,
looking like our inner Solar
System. There are five planets, and
two of them, Kepler-62e (60% larger
than Earth) and Kepler 62f (40%
larger than Earth), are in the star’s
habitable zone.
It was always a conundrum as to
whether exoplanets would be more
likely to be found in star clusters
since many stars made it ‘easier’ to
hunt for planets, or less likely
because any planet-forming
material would be swept up by one
star or another.
Two planets have been found in
the open cluster NGC 6811, showing
that the likelihood of planets
forming around stars in clusters is
similar to other stars in our Galaxy.
Kepler-66b and Kepler-67b both
transit hot stars, and both are
around 3 to 4 times Earth’s size.
Another puzzle has always been
that planets, e.g. Jupiter, thought to
have formed in the outer Solar
System migrated inwards, with the
problem of stopping the planet
before it migrates into the Sun.
Kepler has shown that tidal, or
gravitational, forces act on the
migrating planet, circularising the
orbit and thus halting the inward
migration once a stable circular
orbit has been hit.
Kepler has been trying to sort out
problems with its gyroscopic
reaction wheels for several months,
and may no longer be able to point
accurately. This would mean the
end of a second planet-hunting
satellite, as the French satellite
CoRot ceased its operations earlier
this year due to a computer failure.
Helen Walker
Bringing the latest newsin astronomical research
and observations
p6
Timeline 2003-2013
AstroNews
Above: The first-ever map of an exoplanet—gas giant HD189733b. Made
from Spitzer’s infrared data, it shows temperature variations across the
planet’s cloud tops: higher temperatures are represented in brighter
shades. HD 189733b is a ‘hot Jupiter’, a gas planet orbiting its parent star
much closer than Mercury is to the Sun. HD 189733b completes one orbit in
just 2.2 days. Hot Jupiters are thought to be tidally locked, so one side of
the planet always faces its star. HD 189733b is hotter on its permanently
sunlit side, but the hot spot is offset from high noon by 30°. This asymmetry
is thought to be caused by strong winds pushing the hot spot eastward.
Image: NASA / JPL-Caltech / H. Knutson.
SPA celebrates its 50th year.
Cover of the Jan-Mar issue of
Popular Astronomy is specially
illustrated with art by David A. Hardy. Inside
are congratulatory letters from Patrick Moore,
Sir Martin Rees and Sir Arthur C. Clarke.
2003
A unique stellar alignment—past Presidents at the society’s Golden
Anniversary celebrations. Left-Right: Patrick Moore, Ian Morison,
Barrie Jones, Iain Nicolson, Margaret Penston (then President),
Michael Maunder, Iwan Williams, Jack Meadows, Heather Couper,
Arnold Wolfendale (Patron), Ian Roxburgh and Derek McNally.
Planets around
other stars
November-December 2013 www.popastro.com Popular Astronomy p5
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THE meteorite that came down over
Russia earlier in the year has
started being analysed. A team from
the Ural Federal University collected
bits of the meteorite and the analysis is
showing that it is a common chondrite,
rather than the more exotic iron
meteorite as was speculated, due to its
dramatic entry. There is olivine,
pyroxene, troilite and kamacite present,
showing the rock is indeed from outer
space. Another rock from outer space,
which came down almost 13,000 years
ago, has been tracked down through
Greenland ice cores. The ice cores
reveal a layer of enhanced platinum
and spherical-shaped particles have
been found too in sediments elsewhere,
suggesting that a large meteorite
impact caused the climate to become
colder, which has been linked to the
demise of the North American Clovis
people.
Helen Walker
The
2014
Winter
Olympics,
to be held
in Sochi,
Russia, will
have seven gold medals to be won
during 8th day medal events. These
particular medals will feature
fragments of the Chelyabinsk meteorite.
AstroNews
2003, continued ...
January: New regular
feature Space Cadets for
younger readers of PA,
renamed Prime Space in
April issue.
Ian Brantingham takes
over from Richard Pearce
at the Aurora Section.
David Hardy’s splendid
cover art graces the
Jan-Feb 2003 issue of PA.
Meteorites and impactsMeteorites and impacts
This 112 g fragment of
the Chelyabinsk meteorite
(found between the
villages of Deputatsky
and Emanzhelinsk) is one
of many that were found
within days of the airburst.
It has a thick primary fusion
crust with flow lines; its
heavily shocked matrix shows
melt veins and planar
fractures. Cube 1 cm square.
The Chelyabinsk impact took place on 15
February, deep in the Russian winter,
and a substantial fragment of it survived
the airburst to make in a hole in the
thick icy cover of Chebarkul Lake outside
the city of Chelyabinsk itself (shown at
left). On 16 October Russian scientists
recovered the fragment (possibly the
largest part of the Chelyabinsk meteorite)
from the lake. After hauling it up from
the depths, a giant steelyard
balance weighed it at 654 kg
before the balance tipped
over. As a result, the
meteorite broke into
three pieces.
Monica Grady
becomes SPA
President.
Astrophotography and CCD
imaging Sections incorporated
into Astroimaging Section under
Nik Szymanek.
Most skies across the UK were
wonderfully clear for the the
long-awaited transit of Venus on
8 June.
David Budd’s image of the
transit of Venus.
2004August:
National
Astronomy
Week centred
around Mars,
whose
opposition on
the 28th saw
the Red Planet
approach within
0.37 au from
Earth—its
closest for
60,000 years.
p6 Popular Astronomy www.popastro.com November-December 2013
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THE exoplanet-hunting Kepler
satellite has produced yet
another surprise discovery—an
exoplanetary system orbiting in a
plane tilted highly to the
equatorial plane of its parent star.
Kepler has determined that most
planets have orbits that closely
match their parent star’s
equatorial plane. The most highly
inclined planetary orbit in our
Solar System is 7.25° (Earth).
Kepler has discovered single
planets in highly inclined orbits
before, but this is the first time
that it has been shown in
a multiple planetary
system.
Kepler-56, consists of
two large, closely
orbiting planets (with
orbital periods of just
10 and 20 days) inclined
by a whopping 45° to
their parent star, a giant
four times the Sun’s size.
It is thought unlikely that
these planets formed at such an
angle. Instead, investigations
suggest that they have likely been
levered by
the
gravitation
of a big third
planet in a
different orbital
plane—a planet
revealed by its
gravitational tug on Kepler-56,
rather than by transit. PG
PROFESSOR Peter Higgs, the
scientist who gave his name to the
Higgs boson particle, has won the 2013
Nobel Prize in Physics. He shares the
prize with Francois Englert for their
work in the ‘theoretical discovery of a
mechanism that contributes to our
understanding of the origin of mass of
subatomic particles’.
This mechanism, postulated by Higgs
in the early 1960s, predicts a particle
responsible for giving mass to matter—
a particle known as the Higgs boson.
Having remained a theoretical entity
for half a century, the Higgs boson was
finally discovered last year by a team
from the European nuclear research
facility (CERN) in Geneva, Switzerland.
In a statement released through
Edinburgh University, where 84 year
old Higgs is an emeritus professor, he
said: “I am overwhelmed to receive this
award and thank the Royal Swedish
Academy. I would also like to
congratulate all those who have
contributed to the discovery of this new
particle. I hope this recognition of
fundamental science will help raise
awareness of the value of blue-sky
research.”
The Nobel awards were set up by
businessman and inventor Alfred Nobel
and were first given out in 1901 to
honour achievements in science,
literature and peace. Higgs takes a
place among many Nobel laureates
whose work made a significant impact
in astronomy and cosmology, including:
Albert Einstein (1921) for his work in
theoretical physics and the
discovery of the
photoelectric effect;
Anthony Hewish
and Martin
Ryle (1974)
for their
work on
neutron
stars
and
the
discovery of pulsars; Arno Penzias and
Robert Wilson (1978) for their
observation of the Cosmic Microwave
Background; and Ray Davis and
Masatoshi Koshiba (2002) for their
pioneering work in neutrino astronomy.
A full list can be found at: en.wikipedia.
org/wiki/List_of_Nobel_laureatesPG
p12
2004, continued ...
Shuttle and Spacemen by James Wright (shown
below) is the overall winner of the SPA Golden
Jubilee Design a Constellation competition.
Winner of the
Mars Scrapbook
competition is
Natalie Green
(shown at right
receiving her
award from SPA
President
Monica Grady).
AstroNews
Peter Higgs.
Peter Higgs awarded Nobel Prize
Kepler’s new slant on exoplanets
Ian Morison
becomes
SPA
Instrument
Advisor.
Veteran
amateur
astronomer
Alan Heath
wins Fred
Best award.
2005
Guy Fennimore
(right) presents
the Fred Best
award to
Alan Heath.
Barry Turvey introduces
new merchandise—a
binder for your copies of
Popular Astronomy,a
great new range of SPA
leisurewear and the SPA
teddies.
October: The first SPA
Convention is held at the
Institute of Astronomy,
Cambridge. The event
proves to be a great
success.
November-December 2013 www.popastro.com Popular Astronomy p7
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Advertisements
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p8 Popular Astronomy www.popastro.com November-December 2013
PA_2013-1112 Adlard:PA_2013-1112.qxd 29/10/2013 16:05 Page 7
Iam sitting in my hotel room 240.5 milesfrom home. The transition (yes,
‘transition’ is the right word) from there tohere has been challenging, even thoughthe car journey itself was uneventful.
I have Asperger syndrome, and for all us‘aspies’, changes of routine, changes ofenvironment, in fact changes of every kindcan be fraught with anxiety. But tonight,soon after sunset, I shall see Jupiter shininglike a jewel in the western sky—the sameJupiter I saw from my front porch yesterdayevening, and in almost the same position.And that continuity in the midst of so muchchange will steady me; it will help me to re-orientate myself; it will help me to sleep.
Asperger syndrome (AS) is a form ofautism, a developmental disorder that invarious ways, and to varying degrees(hence the term ‘spectrum disorder’) affectsthe way a person processes information,comprehends the world and relates toothers. According to the National AutisticSociety, around 1% of the UK populationmay have autism. Unlike those with classicautism, however, ‘aspies’ do not usuallyhave learning difficulties and often they areof average or above average intelligence.The long list of celebrities and highachievers who have, or are speculated tohave had Asperger syndrome comprisesmany whose names will be familiar to thereaders of this magazine, including IsaacNewton, Henry Cavendish, John CouchAdams, Marie Curie, Charles Darwin, H.G.Wells, Albert Einstein, Isaac Asimov andCarl Sagan.
As people with AS often feel as thoughthey’ve come from another planet, it’s notsurprising that many of them are drawn toastronomy and science fiction. But asidefrom this understandable interest, timespent with the stars can have a deeplybeneficial effect on those of us with AS, aswell as others on the autism spectrum. Notinfrequently, parents of autistic childrenhave reported a seemingly miraculoustransformation once a map of the stars wasput on their child’s bedroom ceiling.Previously the youngster would not settle atnight and often ended up disrupting thewhole household; now they were soon fastasleep, with the result that their overallbehaviour and well-being improved, andthey responded better to the therapies andprogrammes designed to help them.
There was no star map on my bedroomceiling when I was growing up in the1950s. In fact the syndrome, named afterthe Austrian paediatrician Hans Aspergerwho first described the condition in 1944,
did not become a standard diagnosis until1992. But from my earliest days, I insistedon having my bedroom curtains drawnback at night so that I could see the sky,and even when the stars were hidden bycloud, I would still imagine them there. Letme try to explain why for a chronicallyanxious young person given to frequentpanic attacks, the stars seemed to havesuch a calming influence—as they do tothis day.
Many people find star watching arelaxing antidote to the pace and pressuresof modern-day life. For those of us with anautism spectrum disorder, these interludescan be especially therapeutic. The ‘aspie’brain does not develop the ability to filterout the familiar or see the big picture;instead, it remains permanently attuned todetail and the uniqueness of things. As aconsequence, we find the world aconfusing and unpredictable place whereour senses are constantly being assailed byvast amounts of information that our brainsoften struggle to assimilate.
In order to cope, we rely heavily on order,routine and often rigid patterns ofbehaviour. We try to build connections andderive meaning by applying black-and-white rules, but without specifics, we can beeasily overwhelmed. By contrast with aworld that regularly frightens us with itsnoise and intensity and imponderablecomplexities, the night sky is a haven ofpeace, simplicity and order.
Against a uniformly black background(in rural locations, anyway) myriad pointsof light, in fixed relationship to oneanother, slowly orbit thecelestial pole or riseand set with unfailingpredictability. On anygiven night, we knowexactly where theMoon andplanets will be.There is nothingelse to befuddle themind; there are nojarring sounds orclashing colours—even Earth’snatural satelliteappears restfullymonochrome.And the onlyunexpectedmovement weare likely to encounteris the momentary streakof a meteor.
Some of the autistic children who focuson a map of the night sky at the end of theday find rest by memorising the names ofstars and constellations, and their relativepositions. For me, it has always been thegeometry of those relationships that I havefound harmonious, helping my mind to de-clutter and heal. It is almost as though theconstellations and asterisms provide atemplate or map for the processing brain tofollow.
Those of us with autism want to succeedin relationships, but developing friendshipscan be problematic. We lack the socialskills that ‘neurotypical’ people developnaturally; we struggle to interpret thenonverbal cues which are said to accountfor 85% of all communication betweenhuman beings. Happily, however, the nightsky can be enjoyed by anyone, regardlessof their mental disposition. You don’t evenneed a telescope. Under the cloak ofdarkness, we can converse without havingto make eye contact, which people withautism invariably find difficult. What’smore, the least stressful way we have ofrelating to others is often through a sharedspecial interest, like astronomy.
So if you know someone with an autisticcondition who hasn’t spent time beneaththe night sky, why not introduce them? Gogently, and do not proceed if they show anysigns of fear. However, for those who areinspired by your love and knowledge of theheavens, the benefits could be truly life-
changing, and as enduringas the stars themselves.
Healing starsHealing starsPAUL GREENEWICH explains how
star watching may help some peoplewith an autism spectrum disorder
November-December 2013 www.popastro.com Popular Astronomy p9
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GIVEN an H-alpha telescope,
one can get real satisfaction
from sketching the full solar disk
showing the sunspot groups,
filaments and prominences, such
as those drawn by my colleague
Paul Cannon and featured here.
A DSLR camera can be attached
to a solar telescope using a T-mount to
image the whole disk with one
exposure, or a compact digital camera
can be used with eyepiece projection. If
using a DSLR, a 1.25-inch barrel will
be required for the T-mount, as H-
alpha telescopes tend to have 1.25
focusers. As mentioned in the previous
article, as the sensor of a DSLR will be
further from the blocking filter, a 10 or
15 mm aperture blocking filter will be
required to avoid vignetting of the
image.
Often, however, more detail will be
captured by imaging segments of the
Sun
using a
webcam. As
the CCD sensor of a
webcam is only a few
millimetres in size and its sensor can
be placed closer to the blocking filter
than
with a
DSLR
camera, a
large
blocking filter
will not be required
so the cost of the solar telescope
will be reduced. Reaching focus using a
webcam can be assisted if necessary by
the use of a Barlow lens, removed from
its mount and screwed into the front of
the camera’s 1.25-inch nosepiece. This
will also increase the image scale of
the Sun, giving the potential for higher
resolution images but requiring more
individual images to be combined to
give a full disk image.
The image is essentially
monochrome—though it appears red to
our eyes—and thus a monochrome
webcam will be ideal. This will be
more sensitive than a colour version so
allowing shorter exposures.
I set out to image the Sun using the
Imaging Source DMK 21AU16.AS
which uses a CCD chip having an
excellent ~68% quantum efficiency.
This was initially coupled to a
Solarscope SA60 which had been
kindly loaned to me. The Sun barely
shone when I had the telescope, but
one morning I was able to take a
number of video sequences as gaps
appeared through the clouds. As the
Aspects of instruments andobserving, explained by
IAN MORISONTelescope Topics
Observing the Sun
in the light of
H-alphaPart 2: Drawing and
imaging the Sun
in H-alpha
N
E W
S
Above: Paul Cannon’s
full disk sketch of the
Sun viewed in H-
alpha light on 29 July
2012. It is labeled with
the designated
numbers of sunspot
groups. The SOHO
satellite website
provides these numbers
at sohowww.nascom.
nasa.gov/sunspots
Left: Pastel drawings
of prominences by
Paul Cannon showing
close-ups of
prominences. The
lower sketch (south at
top) is a depiction of
the dramatic
prominence shown on
the southwestern limb
of the main disk
drawing above.
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Sun’s image in the image plane is not
that large, only six individual AVI
sequences were required to cover it,
whilst providing good overlap between
them. This technique is exactly the
same as when imaging the Moon with
a webcam. The individual AVI
sequences were processed in Registax
V4 and the resulting frames
composited into a single image.
The prominences are not as bright,
so a further set of AVI sequences were
taken to correctly expose them. The
prominence and solar disk images then
need to be combined. One method is to
have the two images open side by side
and simply ‘clone’ the prominences
from the brighter image over the, just
visible, faint prominences in the image
exposed correctly for the disk. The
image at right is the result this
process.
Just as a ‘monochrome’ image of the
visible Sun can be coloured, so can
that of an H-alpha image. This can be
achieved in Photoshop simply by
putting the initial image into RGB, 8-
bit mode, and then duplicating it—
Layer > Duplicate Layer. The colour
box is clicked on and a set of suitable
R, G and B numbers placed in the
panel that opens up. A good starting
point would be R = 231, Green = 33
and Blue = 11. The paintbrush is then
used to paint over the duplicate layer
to give a completely red image and, in
Layers, the blending mode is changed
to ‘Colour.’ The layers are then
‘flattened’—Layer > Flatten Image—
and the resulting image saved. The
resulting colourised version of the
solar image above is featured in this
issue’s Showcase on p47.
A Barlow lens can be used to
increase the image scale either by
using the full Barlow unit or by
screwing in its lens element into the
front of the webcam barrel to give a
lesser increase.
Rather than producing full disk
images I have tended to image
interesting areas of the Sun and two of
these are shown below. That on the
left is with the webcam mounted
directly into the telescope eyepiece,
whilst that on the right is with the
insertion of a 2.5× TeleVue Powermate
Barlow to give a detailed image of a
particularly interesting region.
In all, solar observing can be quite a
rewarding aspect of amateur
astronomy which, almost by definition,
can usually be done in the warm. Why
not give it a try?
Next issue: DSLR cameras with
modified infrared filters.
Two H-alpha webcam images of parts of the solar disk.
Images by Ian Morison.
Right: A full disk composite image of
the H-alpha Sun captured using a
webcam and stitched in Microsoft ICE.
The colour version of this image is
featured in this issue’s Showcase on
p47. Images by Ian Morison.
Telescope Topics
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THE death of Sir Patrick Moore at
the end of last year has provided an
opportunity to not only look back over
his long and distinguished career but
also to celebrate the achievements of
some of those who worked alongside
him. One of these is space artist David
Hardy who recalled some of their
collaborations in Spaceflight, the
magazine of the British Interplanetary
Society.
David’s connection with Sir Patrick
dates back to 1954 when a friend of his
had visited Patrick and shown him
some of David’s artwork. An exchange
of telegrams followed in which Patrick
asked for eight black-and-white
illustrations for a book, Sun, Myths and
Men. David remembers how he had
only five days to do the job before he
joined the RAF to do his National
Service. In fact, the finished pictures
were only put in the post as David set
off to start his tour of duty.
Other collaborations followed. One
was another book, The Challenge of the
Stars, which the publishers then
thought too much of a leap into the
future. By the time mankind had
visited the Moon, it was thought the
time for the book had finally come and
it even enjoyed a revival as The New
Challenge of the Stars alongside the
release of the first Stars Wars film.
David’s work with Patrick spanned 50
years, their last major venture together
being Futures: 50 Years in Space which
showed how our ideas of both space and
space travel have changed over time.
David’s earlier pictures showed spiky
lunar landscapes which became more
smoothed and rounded by the 1970s
while streamlined spaceships and space
stations conversely became more spiky.
David also previewed human
exploration to come on Mars or Saturn’s
moon Titan. In this last subject, David
updated a classic image of Saturn
suspended in Titan’s sky created by
Chesley Bonestell.
Over the years, David’s techniques
have moved on too. Those first
illustrations in 1954 were done with
scraperboard; many later ones are in
gouache while the most recent pictures
are produced digitally.
A striking image is David’s cover for
another Patrick Moore book, The Boys’
Book of Astronomy (1958). Here David
did both the lettering and illustration
which saw him use an airbrush for the
first time to show a spiral galaxy
hovering over an observatory dome.
For more about David Hardy’s work
visit www.astroart.org.
Amateur SceneMemories of working alongside Sir Patrick
Ian Crawford
takes on SPA
Presidency.
Jeff Stevens becomes the new
SPA Webmaster and Michael
Hezzlewood is appointed as
Planetary Section Director.
Dusko Novakovic takes on role
as Light Pollution Liaison Officer.
April: Ian Morison’s first
Telescope Topics pages.
July: Meetings now held at the
SOAS Khalili Lecture Theatre.
SPA
visits to
the
University of London
Observatory (Feb) and
Jodrell Bank (Jun).
March: 2nd SPA
Convention, held at the
Institute of Astronomy,
Cambridge. Another
big success, it was
visited by the Astronomer Royal, Professor Sir Martin Rees.
Emily Baldwin becomes editor of Prime Space.
PETER WADE’S roundup oflocal astronomical society
news and events
David and
Sir Patrick,
shown by
the artist on
the surface
of Saturn’s
biggest
moon Titan
in the 1970s
(left) and in
the (real)
study of
Farthings,
Selsey, in
2003.
Images:
David A.
Hardy.
20072006 Mandy Bailey, the new SPA Publicity Officer. Lord Rees and
Robin Scagell.
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THESE days, a cloudy
night doesn’t mean you
can’t do any astronomy. For
starters, you can look for
messages from aliens
through SETI@home. This
citizen science project has
involved some hundred
thousand computers
worldwide and has inspired
other projects including
Einstein@home and
asteroids@home as well as
ones like malariacontrol.net
completely outside the field
of astronomy.
Google Earth looks up as
well as down (click on the
Saturn icon on the toolbar)
and opens up sky maps as
well as maps of objects in the
sky such as Mars and the
Moon. Mobile devices will
additionally give you a sky
view in the direction you are
looking.
Galaxy Zoo involves you in
the classification of galaxies
on images from the Sloan
Digital Sky Survey. Some 40
million galaxies have been
classified and along the way
the project has thrown up
odd objects such as Hanny’s
Voorwerp, a strange filament
apparently associated with a
galaxy, and, more recently,
new objects such as the so-
called ‘green peas’.
Cloud spotting
on cloudy nights
may not seem an
inspiring activity
unless the clouds
are ones of gas
in the Milky
Way. Here
projects are
concerned with
identifying the
edges of gas
bubbles.
Add to this the
use of remote
telescopes and images from
space such as from SOHO,
cloudy nights become lively
nights for astronomy where
you can use existing
packages, participate in
mass projects or look at the
research findings of others.
Amateur Scene
2007, continued ...
Young Stargazers Section is
launched, with Emily Baldwin
its ‘Chief Stargazer’.
p14
Cloudy nights can be lively nights
SPA participates in IAU’s
International Year of
Astronomy, themed on 400th anniversary
of the telescope’s first astronomical use.
Members’ Open Telescope evenings held
around UK, mainly on the dates of Spring
and Autumn MoonWatch, and the Jupiter
and Schools MoonWatch. SPA also runs
Telescopes for Schools project and
produces an associated DVD-video.
March: 3rd SPA Convention in
Cambridge. Another excellent event.
Jeff Stevens takes on Occultation Section.
Above: SETI@home began in
May 1999. Based on the
Drake Equation a conclusive
alien signal is likely to be
detected before 2025.
Below: Zoom-in of the Apollo
16 Descartes landing site in
Google Earth, Moon view.
2009New President,
Helen Walker.David
Scanlan
takes on the Variable
Star Section.
July: Prime Space
incorporated into
Young Stargazers’
section in PA.
Dave Pearson briefly
takes on the role of
SPA Webmaster but is
replaced by Kevin
Brown later in the year.
2008
Emily
Baldwin.
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Amateur Scene
THE British Astronomical
Association has established The
Sir Patrick Moore Prize to be
awarded annually in recognition of
groups or individuals who have
encouraged a public interest in
astronomy, contributed to our
understanding of the history of
astronomy, carried out collaborative
work, encouraged participation in
observation by young people or, for
younger people themselves, done
outstanding observational work.
BRECKLAND Astronomical
Society held their autumn star
party under the dark skies of Haw
Wood Caravan Park in Norfolk in
September. The park holds a Dark
Sky Discovery Site award—Milky
Way class—from the Science and
Technology Facilities Council.
MEMBERS of Liverpool
Astronomical Society took
their solar telescopes along to an
open day at Wharncliffe Allotments
on 8 June. The Sun obliged,
allowing viewing in H-alpha light
and in white light through mylar
filters. Meanwhile Liverpool AS
meetings continue with Dr Mark
Hadley on the use of chirality in
the search for extra-terrestrial life
(15 November) and members’ talks
on 13 December. The meetings
start at 7pm in the Quaker Meeting
House, School Lane, Liverpool.
MEETINGS of Orwell
Astronomical Society’s
Newbourne Observing Group
continue in Newbourne Village Hall
from 7pm on 11 and 28 November
and 9 and 19 December. The
society’s annual open weekend at
the Orwell Park Observatory will
meanwhile be held on 22 and 23
November from 7.30pm.
Out and about
PA is redesigned and moves from
quarterly to bimonthly publication; it
now includes section reports.
Martin Morgan-Taylor
redesigns SPA
website.
March: 4th SPA
Convention in
Cambridge. Another
great event.
Mell Jeffery takes
post as Occultation
Section Director.
IF anyone’s bought a security light recently,
they’ll probably find a leaflet in the packaging
entitled Getting Light Right—simple tips to get
your floodlight working best for you and the
environment. The leaflet is produced by the
Department for Environment, Food and Rural
Affairs alongside the Campaign to Protect Rural
England, the
Institution of Lighting
Professionals and the
Campaign for Dark
Skies, and is the
latest step in a
campaign spanning
almost 25 years to reduce light pollution.
Over-bright domestic lights are one of the most
annoying sources of unnecessary illumination.
Under its heading Be considerate of others, the
leaflet points out the importance of choosing the
right bulb for the job. A 150W bulb is
recommended as appropriate for lighting small
areas and less wasteful of both energy and money.
The leaflet also warns against intrusive lighting
affecting neighbours and points out that fines may
be imposed if such lighting is judged to constitute a
statutory artificial light nuisance by the local
authority.
Fight night blight,
get light right
20112009,
continued ...
Peter Grego
takes on writing
Deep Sky
Notes after
death of Dave
Fletcher, and
Jerry Stone
takes over from
Dave Tipper as
writer of Space
Exploration
pages in PA.
John Zarnecki, new
SPA President 2010.
Helen Walker
becomes
Treasurer, taking over from
Leslie Green who had done
the job since 1967.
New Planetary Section
Director Andrew Robertson
and Martin Morgan-Taylor
becomes Light Pollution
Liaison Officer.
April: Dale Holt becomes
writer of Deep Sky Notes.
November:The final SPA News Circular.
2010
Brian Cox becomes honourary
member, in good
company with
honourary member
Brian May.
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SPA’s 60th
anniversary.
A range of
special days are
organised
around the UK
during the year.
Wonderful tribute
paid to Sir Patrick Moore at January meeting.
David A. Hardy designs special 60th
anniversary cover for Mar-Apr issue of PA.
2013
Last year I reported some of the
research Kevin Kilburn had done on
the early rocket pioneers in the North
West of England and, in particular, Eric
Burgess (Amateur Scene, Popular
Astronomy September/October 2012).
The first flights of these rocketeers is
now recorded in a plaque set up at
Clayton Vale by Manchester and
Salford Astronomical Societies along
with the British Interplanetary Society
(BIS). Further background has been
provided by Gurbir Singh writing in the
BIS magazine Spaceflight.
Eric Burgess (pictured at
right) had formed the
Manchester Interplanetary
Society in 1936. The following
year the society was set for
the test launch of thirteen
experimental rockets, all
designed and made by the
members themselves some of
whom, photographs reveal,
were still in short trousers.
The experiments were very
hazardous with one of the
rockets actually exploding
and causing injury to
three of the pioneers,
one of whom required
hospital treatment.
The test flights
attracted
considerable
attention, not least
because the
participants were
summoned to appear
in court under the
1875 Explosives Act!
As well as the
Manchester group,
other rocket groups
are known to have
formed in Hastings,
the Midlands, Leeds
and Paisley during
the 1930s.
Gurbir Singh notes
an interesting
connection between
Eric Burgess and
Salford AS. While
living in Macclesfield
in the 1950s Burgess had used a 45 cm
reflector at Jodrell Bank whose purpose
was to examine the optical counterparts
of radio sources detected by the famous
radio telescope then still under
construction.
In the 1970s the telescope and its
dome found a new home under the
curatorship of Salford AS and during
the late 1970s Gurbir himself, as a new
member of Salford AS, looked through
this very telescope, one that Burgess
had used 20 years earlier, shortly before
his move to the USA.
Explosive start for
northwest rocketeers
Clayton Vale, 27 March 1937. Pioneer rocketeers (left to
right) Eric Burgess, Bill Heeley, Trevor Cusack, Harry
Turner. Image: Philip Turner.
Host societies
welcome BAA
BRISTOL Astronomical Society
hosted a weekend meeting of the
British Astronomical Association (BAA),
The new, the old and the ancient, in
September. Bristol AS recently
celebrated its 70th anniversary. It has
over 120 members and gathers weekly
at Bristol Grammar School to hear
guest speakers or for informal club
nights. The society observatory is open
to the public on Saturday evenings.
Details of Bristol AS can be found at
www.bristolastrosoc.org.uk
This splendid cake, made to mark the
Bristol AS’ 70th birthday, was presented
at the society’s anniversary dinner on
February 2013.
IN October a BAA Back to Basics
workshop was hosted by East Sussex
Astronomical Society. The society has
grown rapidly and currently meets at
St Mary’s School, Bexhill. East Sussex
AS has its own observatory and has a
lively programme of outreach activities
including solar observing on the
seafront at De La Warr Pavilion (shown
below, with some expectant observers).
Burgess.
Amateur Scene
Alan Clitherow becomes Planetary
Section Director.
George Ford and Ezzy Pearson take on Young
Stargazers pages, and Helen Walker starts at Space
Exploration.
October: Special meeting at South Downs Planetarium.
Computing Advisory Service disbanded. Graham
Bowden-Peters had been in post since its inception in
1993. Tony Markham takes over from Alastair McBeath
at Meteor Section
December: Sir Patrick Moore, one of the founder
members of the society, dies.
20122011,
continued ...
May: After
more than a
decade, Alan
Longstaff
retires from
writing
AstroNews.
August: Special
SPA meeting at
the Greenwich
Planetarium.
Derek Ward-Thompson, the
new SPA President 2012.
Pla
tinum
Jubile
e:
2023
November-December 2013 www.popastro.com Popular Astronomy p15
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WATER is a substance that is easily takenfor granted. There is a lot of it about—
the oceans cover about 70 percent of thesurface of planet Earth.
The importance of water to life on Earth isalso something else we take for granted.Although it is common to refer to life onEarth as being carbon-based, it might bemore accurate to think of it aswater-based. A typical human bodycomprises about 60-70 percent water butonly 18 percent of carbon. Although ahealthy human being can survive for about amonth without carbon-based food, at bestwe can last a week without water.
Three states of matterIt should come as no surprise, therefore, thatthe habitable zone around a star is definedas the region where liquid water can exist.To a physical chemist, however, the mostinteresting fact about water on this planet isnot that it exists as a liquid, but that it can,and does, exist in all three states of matter—solid, liquid and gas.
Experiments on the formation of organicmolecules have demonstrated theimportance of liquid phase and gas phasewater for the prebiotic syntheses of proteins,whereas the existence of solid and liquidwater may have been more important for theorigin of nucleic acids. So what are theseproperties of water in all three phases andhow have experiments demonstrated theimportance of all three phases?
Most people are familiar with the solid toliquid transition of water. When ice iswarmed above 0ºC—whether it is in theform of snow, or ice cubes in a cold drink—it melts. Equally familiar, if we heat water to100ºC, for example in a saucepan or kettle,it boils, changing from a liquid to a gaseousstate. Scientifically we would say that thethermodynamically stable form of water,below 0ºC, is a solid; between 0 and 100ºCit is a liquid, and above 100ºC it is a gas.
Water can transition from the liquid to thegas phase below 100ºC. This is the familiarprocess of evaporation, typically seen in thedrying of puddles or of washing on a line.There is a well-defined relationship, or
equilibrium, between temperatureand pressure, and the amount ofwater that exists in theatmosphere below 100ºC,the boiling point.Formally this is called thevapour pressure,
although it isbetter known as thehumidity of the air.
Water molecules canalso move directly from the solidphase to the gas phase by the process ofsublimation. The amount of water that canexist in the gas phase in equilibrium with ice,however, is very small. At very lowtemperatures this amount is vanishinglysmall, which explains why icycomets and icy moons can existin space and do not simplysublime. At a temperatureof -200ºC, an icy bodythe size of Enceladus (thesixth largest satellite ofSaturn, 1,584 km across) will eventuallydisappear by sublimation into space, but theprocess would take something of the orderof six billion years.
Distribution of waterThe existence of water in the liquid and gasphase is important for the distribution ofwater across a planet whose surface is amixture of rock and water. Although there isno doubt that sustainable life could existsolely in the oceans, the colonisation of landby water-based life forms is only possible ifthere is a mechanism that distributes waterfrom the oceanic reservoirs to the dry land.
On Earth this is achieved via the water orhydrologic cycle. In a process driven by heatfrom the Sun, liquid water in the oceansevaporates into the atmosphere, or gasphase. Rising currents of warm air carry thewater vapour to the higher, cooler parts ofthe atmosphere where it condenses backinto liquid water in the form of clouds. Rainfrom the clouds spreads the water cross theland masses, where under the influence of
gravityit runs off and returns to the oceans. Thusland-based life is provided with a constantsupply of water.
Variations in temperature and pressureacross the Earth lead to variability in theamount of water that is present in theatmosphere. In warm tropical areas theamount of water vapour may be close to themaximum, a maximum defined as 100percent relative humidity. In contrast to this,in the dry valleys of the Antarctic, there isvirtually no water in the atmosphere. Theaverage relative humidity at the South Pole is0.03 percent, much drier than any desert.
These differences in temperature andhumidity have led to the evolution of a widevariety of life forms. Such a variety of livingorganisms may be essential for the long termsurvival of life upon a rocky planet. Asclimate changes, or in the event of extra-terrestrial disaster such as the Chicxulubimpact 65 million years ago, the loss of onelife form can be compensated for by thegrowth of other populations.
The GoldilocksZone, refinedThe GoldilocksZone, refinedThe fact that water exists in solid, liquid and gas formon planet Earth was essential to the development oflife on Earth, and remains vitally important to lifetoday. TONY AUFFRET plumbs the subject.
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Climate and diversityWhen looking for planets that are not only
within a habitable zone around a star, butare likely to support life, then an axial tiltwhich introduces seasonal climate changesmay be a valuable clue. Perhaps, as in thecase of Earth, the presence of a largesatellite that stabilises the tilt may increasethe likelihood of life being present on thatplanet.
The equilibrium between liquid water andgaseous water, therefore, is important notonly for the support of life across the surfaceof a planet but also for the generation ofdiversity. When considering the survival oflife over long periods of time, such diversitymay be an important consideration. Butwhat of the solid liquid equilibrium—thefamiliar ice and water transformation—whatrole does that play? Life in a cold climateneeds particular adaptations, but perhapslife in any climate zone requires appropriatemodification, brought about by the processof evolution.
Whereas a cold climate may presentspecial risks and challenges to life, and theArctic and Antarctic regions of the Earth aresparsely populated, freezing itself is acompletely different challenge. Put almostany terrestrial life form—bacterial, fungal,plant or animal—in a freezer and the resultis almost invariably fatal. There areexceptions, the presence of some veryspecialised and rare adaptations, or somevery particular pre-treatments, both of whichrequire a period of acclimatisation. Ingeneral, however, freezing kills. So how canthis process be of value in defining thehabitable zone around a star?
Defining the habitable zoneTo answer that question, and also why theliquid/gas phase transition of water isimportant, we have to consider the buildingblocks of life and how they came intoexistence. Ask anyone about the origin of lifeand the most likely image to come to mindis a primordial landscape with a lake and avolcano erupting in the background, withlightning flashing across a heavy sky. Inmany ways this scenario is derived from a
classic experiment carried out by StanleyMiller and Harold Urey at the University ofChicago in 1952. In this experiment a flaskof water was boiled and the steam passedinto a second flask containing an oxygen-free atmosphere containing hydrogen,methane and ammonia. Although we take itfor granted that oxygen is present in ouratmosphere, it is a very reactive molecule. Inthe absence of photosynthetic life forms,which generate gaseous oxygen, all theoxygen would be locked up in the form ofoxides, including water and mineral oxides.In the Miller experiment, sparks were passedthrough the gaseous mixture to simulatelightning and the ‘atmosphere’ was thenpassed through a condenser to trap thewater as a liquid, which could then beevaporated to continue what was asimulation of a hydrologic cycle.
After about a week of recirculating thewater, Miller and Urey analysed thecondensed water and found that 10-15
percent of the carbon from the atmospherehad been trapped as organic molecules.Included in this mixture of organic moleculeswere eleven types of amino acid. The waterhad been changed into a soup of organicmolecules, supporting the primordial orprimeval soup theories that had earlier beensuggested by Alexander Oparin and J.B.S.Haldane. What Miller had established wasthe importance of liquid and gas phasewater in abiogenesis.
In a different and much longer termexperiment Miller investigated the role of theliquid/solid phase (water/ice) transformationof water in the origin of organic materials. Inan extraordinary experiment lasting morethan 25 years, Miller froze a solution ofammonia and cyanide to -78ºC.
Chemistry at low temperatureConventional wisdom says that at such a lowtemperature, very little chemistry, if any, may beexpected to take place. Miller found that,
The Three Statesof MatterOn the Earth, moleculescan exist in three states,or as scientists wouldcall them, phases—thesolid, liquid and gas phases.
The solid phase is the most stable,lowest energy state. In the solid phasemolecules are ordered in fixed, repeated,spatial arrangements, they form a crystal.Ice is the solid, crystal, phase of water.
If we add energy, typically heat, to a crystalit will melt and form the next phase, theliquid phase. Liquids flow because althoughattractive forces keep themolecules closetogether, the moleculeshave too much
energy toremain
in fixed positions. This is the most familiarphase of water on the Earth.
Adding even more energy will overcomethe attractive forces and the liquid will boil toform a gas, steam in the case of water. Theenergy required to change from a liquid toa gas is much greater than that need tochange a solid into a liquid.
It is possible to go directly from a solidto a gas—a process called sublimation,or from a liquid to a gas without boiling
by the process of evaporation. When agas turns to a liquid, typically by cooling, itis said to condense, and a liquid turns to asolid by the process of crystallisation. Thisprocess is also called solidification, or in thespecial case of water, freezing.
The 1952 Miller-Urey experiment.
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The buildingblocks of lifeEven the simplest living organisms area very complex mixture of biochemicals,molecules both large and small. The mostcomplex molecules of life are large polymerseither of nucleic acids, proteins orcarbohydrates. Viruses, the simplest knownorganisms, consist essentially of a long chainof nucleic acid wrapped in a protein coat. Asthey are incapable of replicating themselveswithout hijacking the cellular mechanisms ofother organisms, opinions differ as to whetherthey can be classified as living.
In general, nucleic aids andproteins are called thebuilding blocks of life. Theinformation required for life isstored in the DNA molecule,
an extremely long double helixof two complementary strands of DNA.
Each strand is built from only four buildingblocks, the nucleic acid bases generallyknown by their abbreviations A, T, G, and C.The sequence of the building blocks containsthe code for life.
Proteins are very versatile molecules, andcan be structural, bone is mineralised protein,functional, as in muscle, or catalytic, as inenzymes which control the chemical reactionsof life. The building blocks of proteins are
amino acids which are linked head to tail infolded chains. Terrestrial life, uses twentyamino acids to construct its proteins. Thesequence of amino acids in a protein isdetermined by the sequence of the bases inthe DNA code, and it is the sequence of theamino acids that determine the function of theprotein. Very few of the possible proteinstructures actually exist. If we take a proteincomprising a sequence of 100 amino acids,and that would be classed as a small protein,and were to construct one molecule of everypossible sequence, the resultant mass wouldweigh about 2 x 10105 kg. This is significantlymore than the mass of the known universewhich is estimated to be between 3 to 8 x1052 kg.
despite the low temperature, the mixture notonly contained some amino acids, but alsonucleobases—the building blocks of RNA andDNA. Other scientists, notably US-basedLeslie Orgel and German-based ChristofBiebricher showed that not only could shortchains of RNA molecules assemble underfreezing conditions, but that if the system wasprimed with a strand of RNA, acomplementary strand was synthesised againstthis primer—effectively demonstrating thatnucleic acid replication, an essential featureand prerequisite of terrestrial life, was possible.
Like Miller’s initial study, many of theseexperiments were left for long periods of time,as the expectation is that chemical reactionsslow down as the temperature drops. Thispresents a paradox, and one which initiallyraised scepticism over the results, why do thesereactions proceed faster at lowertemperatures? The answer lies in the freezingprocess, the liquid/solid transformation ofwater which has two important aspects. Firstly,an ice crystal, unlike many other crystals(notably gemstones), does not allow anyimpurities within its crystal lattice—it is puresolid water.
Secondly, when an aqueous solution freezesit does not totally solidify. Pure solid water iceforms but some of the water remains unfrozenand this unfrozen water is in the form of asolution which contains all the solutes. Ineffect, this residual solution is much moreconcentrated than the original solution. Theamount of ice that forms, and the resultantconcentration of the residual solution, iscontrolled by the temperature, and in terms ofphysical chemistry may be mapped as a phasediagram. As the temperature is lowered andthe residual solution becomes moreconcentrated, eventually there comes a pointat which there is too little water to dissolve thesolute. At this point (the eutectic point) thesolute comes out of solution and theremaining water freezes.
For a solution of sodium chloride (salt) theeutectic temperature is -21ºC when theconcentration of salt reaches 4 moles per litre.Seawater contains about 0.5 moles per litre ofsodium chloride, which, therefore can be
concentrated eight times by freezing. Solutionsof other salts may have even lower eutectictemperatures.
The effect of freeze concentration,sometimes called eutectic concentration, isthat molecules are squeezed into a smallvolume of liquid, increasing the chance ofreactions occurring through molecularcollisions. In 1986, Cambridge-based scientistFelix Franks demonstrated a 60 fold increasein the rate of oxidation of ascorbic acid uponfreezing to temperatures close to the ascorbicacid solution eutectic temperature of -18ºC.Increases in chemical reaction rates of thisorder of magnitude, however, may beconservative estimates. The important point isthat many, if not most materials, do notcrystallise from frozen solutions in a classictextbook manner, but may be cooled to lowertemperatures, greater degrees ofconcentration and a greater chance ofchemical reaction.
The mechanism of crystallisation is complexand at these low temperatures, crystals maysimply fail to form or to grow. A frozen solutionof sugar (sucrose), for example, does not showsugar crystallisation at -10ºC, the eutectictemperature, but continues to concentrate untilit becomes so viscous that, at -32ºC, it is assolid as glass. Once this point, the glasstransition temperature, is reached, there is nofurther change or concentration on loweringtemperature. The addition of salt (sodiumchloride) significantly reduces the temperatureat which this glass viscosity is reached andunfrozen, highly concentrated solutions ofsugar and salt can exist at -90ºC, the coldesttemperature recorded on Earth. Rather like thevariation in eutectic temperatures, frozensolutions of other materials have different glasstransition temperatures. A solution of glucosehas a glass transition temperature of -43ºC,whereas a frozen solution of zinc chloridevitrifies at -88ºC. Water itself will turn to a glassat -138ºC, although very special techniquesare required to prevent it freezing long beforethat temperature can be reached.
Simple organic molecules, frozen inseawater, may therefore exist as highlyconcentrated solutions, with concomitant
increases in chemical reaction rates, at verylow temperature, explaining the importance offreezing in the abiotic generation of biologicalmolecules.
In searching for life on other planetsidentifying the habitable zone, the zone whereliquid water can exist is an important step inincreasing the probability of success. Whatdifferentiates the Earth from other planets inthe solar system is that water can exist in allthree states of matter. The importance of thisdifferentiation has been demonstrated by ourcurrent understanding of how the molecules oflife may have been generated in an abioticenvironment. Redefining the Goldilocks Zone,narrowing down the search to find zones orplanets where water can exist in all three statesof matter may significantly increase thechances of success in the search for extra-terrestrial life. If we then add an additionalrefinement that climatic variation leads to adiversity of life forms, increasing the chances oflong term life despite inevitable naturaldisasters, then planets with an axial tilt and astabilising moon should be prime targets in thesearch.
Organic chemicals. Molecules that containcarbon, e.g. methane, amino acids, sugars.
Abiogenesis. The theory that life can arisestarting with the combination of inanimatematter.
Crystal lattice. The regular three-dimensionalrepeating pattern of atoms or molecules thatmake up a crystal.
DNA. Deoxyribonucleic acid, the chemicaldatabank of life on Earth. The sequence of 4bases in this linear polymeric molecule, theDNA code, stores the information necessaryfor life.
RNA. Ribonucleic acid. A linear polymer ofnucleotides that acts as the messengerbetween the DNA databank and the cell’schemical synthesis machinery.
Tony Auffret is runs taPrime Consulting and isthe UK Director of the BioUpdate Foundation.His scientific background encompasses thebiochemistry of protein evolution and thephysical chemistry of biopreservation.
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Mars before the flyby of Mariner 4When I became fascinated by astronomy in1951 at the age of ten Mars had long beenthought to bear life. This enchanting beliefwas held by many professional astronomersand by the great majority of the generalpublic—that is, until the flyby of Mars byMariner 4 in 1965.
Mars is our planetary neighbour goingoutward from the Sun. Most of the late 19thCentury ‘vital statistics’ of Mars differ littlefrom the present values (see table below),though they are now known to greaterprecision.
The ‘canals’ of MarsMartian surface features were first recordedin the middle of the 17th Century, but I’ll skipto 1877, when the infamous history of thecanals of Mars began.
The 1877 opposition occurred whenMars, in its modestly eccentric orbit, wasnear perihelion, ‘merely’ 56 millionkilometres from Earth. During that perihelicopposition many astronomers madedrawings of Mars, but it was the those madeby the 42 year old Italian astronomer
Giovanni Virginio Schiaparelli that drew alot of attention. He used the 22 cm (8.6-inch) aperture Merz refractor that had beeninstalled at Brera Observatory, Milan, in1862—too late for the previous perihelicopposition in 1860. As well as refining themaps of the previously known features, hedrew narrow linear features that he called‘canali’, Italian for ‘channels’.
A few English-speaking astronomers madethe all too easy transliteration of ‘canali’ into‘canals’, thus implying their construction byi n t e l l i g e n tbeings. Thea s s u m e dpurpose of the‘canals’ wasto eke out thewater supplyof a dry world,as indicatedby thew idespreadred deserts.What wasvisible, it wassaid, was not
the water in the canals but strips ofvegetation running along them.
The main proponents of intelligentMartians were the American astronomersPercival Lowell (1855-1916) and hiscontemporary William Pickering (1858-1938). Lowell came from a wealthy Bostonfamily. He graduated from Harvard
‘Vital statistics’ of Mars and Earth compared. All Solar Systemplanets have ages of 4.6 billion years.
Mars, beforethe Space AgeMars, beforethe Space AgeProfessor BARRIE W. JONES takes a look at ourknowledge of the Red Planet prior to the advent ofspace probes. While many mysteries of Mars havesince been explained by robotic exploration, many of theplanet’s features and phenomena remain enigmatic.
Mars in opposition atperihelion. Perihelic
oppositons arewhen Mars is
close toperihelion,
and are spaced by
either 15 or17 years.
Mars in opposition
at perihelion.
Graphic: BWJ / PTG.
Earthperihelion
Mars, asseen by space
probes and the human eye. Graphic: PG.
Giovanni Schiaparelli,depicted on a 2010
Italian postage stamp.
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University in 1876 with a distinction in mathematics, and in the 1880stravelled extensively in the Far East. He returned to the UnitedStates in 1893, determined to study astronomy, particularly Mars.
Lowell used his wealth and influence to construct anastronomical observatory in Flagstaff, Arizona, on a hill risingto an altitude 2,210 metres (7,250 feet)—an elevation thatbecame known as Mars Hill. It is an excellent site, with verygood seeing and few cloudy nights. Building started in 1894with Pickering helping the construction. The main telescopehas a 62 cm (24-inch) objective lens by Alvan Clark & Sons.Lowell lived with his wife in a house on Mars Hill where hismausoleum is also sited.
Lowell adopted the ‘canal’ interpretation of Schiaparelli’s‘canali’ and he spent 15 years observing and mapping them.However, most astronomers could not see these features, soLowell’s views had very little currency in the professional astronomyof the time. Right: Mars by Lowell (south at the top).
During the perihelicopposition of 1909, the
1.56-metre (60-inch)reflector on MountWilson in southernCalifornia wasused to examineMars. No canalscould be seen,leading to theconsensus thatLowell had simply
m i s i n t e r p r e t edirregular geological
features that wereprobably the result of
erosion. The flybys of Mariners 4, 6,
and 7 in the 1960s, and theMariner 9 orbiter in 1972 finally put the
kybosh on Martian canals. They are evidence of intelligence, butit’s at the eyepiece end of the telescope.
So what was Lowell seeing? Several explanations have been putforward. One is that the viewing of approximately co-linear spotsand streaks at the limit of visibility leads to the brain tidying themup. But missions to Mars have seen no such features at the greatmajority of places where Lowell’s ‘canals’ were located. It is nowwidely believed that his ‘canals’ were an optical illusion. Onerecent view is based on Lowell’s habit of stopping down thetwenty-four inch objective lens to a substantially smaller aperture.This can result in an image contaminated by retinal shadows ofthe eye’s blood vessels.
Schiaparelli’s1877 map ofMars (southat top). FromOservazioniAstronomichee FisicheSull’asse diRotazione eSullaTopografiadel PianetaMarte (1878).
Fantastic fictionBut even though astronomers have longrejected Martian canals, authors offiction have clung on to the belief. Thefirst of these is H G Wells, whosemagnificent The War of the Worlds waspublished in 1898. Thereafter followeda steady flow of science fiction withcanals on Mars, including Red Planet(1949) by Robert A Heinlein and TheMartian Chronicles (1950) by RayBradbury. Great fun!Martians on Earth. From the first edition
of Wells’ The War of the Worlds.
Lowell at the Clarkrefractor, Mars Hill.Percival Lowell (left) and William Henry Pickering, both pictured around 1909.
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Albedo features andthe atmosphere It was well established by the19th Century that there arethree types of albedo featurevisible from Earth: the brightorange-red areas, which arethe most extensive of thethree; the dark areas, whichare the next most extensive;and the white polar caps, themost variable in extent. ThatMars has some sort ofatmosphere was indicated, forexample, by dust storms thatobscured albedo features,sometimes planet-wide.
Rather than go through in historical orderevery advance in our knowledge of Mars, I’llconcentrate instead on the picture justbefore 15 July 1965 when the NASAspacecraft Mariner 4 flew past Mars’southern hemisphere at a distance of only9,800 km.
The bright orange red areasThe bright orange areas had long beenconsidered to be deserts of sand and dust,The coloration of the areas was assumed bymany to be due to ferric oxide (‘rust’) Fe2O3.Audouin Dollfus (1924-2010) conductedspectrometry from a stratospheric balloon inwhich he flew and showed that indeed ferricoxide accounted for the colour.
The dust raised by winds in the thinatmosphere were held to cause theoccasional local or global obscuration ofthe Martian surface.
The dark areasThe dark areas were seen to change inshape, extent, and contrast, some of thechanges being seasonal. By 1892 mostastronomers thought that they were not seas.Powerful evidence for this conclusion is thelack of a bright spot that extended bodies ofwater exhibit when illuminated by the Sunand viewed from above. This spot is thereflected image of the Sun. Also, the darkareas exhibit the un-sea-like behaviour offaint structures that varied seasonally.
Most astronomers thought that the darkareas were vegetation, changing in extentand contrast in response to the seasons. Afew astronomers thought that they consistedof minerals, the seasonal changes the resultof the dampening of hygroscopic mineralsby water vapour released from the summerpolar cap.
The American astronomer DeanMcLaughlin (1901-1965) was closer to thetruth in his belief that the dark areasconsisted of volcanic ash placed in semi-permanent patterns by the prevailing winds.
The popular view among the wider publicwas the vegetation model. After all, this wasin accord with the hope that Mars wasinhabited.
The polar capsThe polar caps exhibit changesin extent in accord with theseasons, smaller in summer,larger in winter. They werethought to consist of water iceand snow. The caps providedfurther evidence for anatmosphere, without which thevolatile polar caps would belost to space throughsublimation.
The atmosphereThe dust storms and the whiteclouds (see below) was furtherevidence for an atmosphere.That the atmosphere is thin was indicated bythe large diurnal swings in the temperatureof the Martian surface.
Analyses of solar radiation scattered byMars plus wobbly assumptions led toestimates of the mean surface pressure in therange 80-120 millibars, significantly lessthan the Earth’s 1013 millibars. The columnmasses are more similar because of Mars’slower surface gravity, 3.7 m/s2 versus 9.78m/s2, giving column masses of 0.21-0.34for Mars and 1.03 for the Earth, in units of10 000 kg/m2.
The composition of the Martianatmosphere was determined by spectrometryfrom the Earth’s surface. Suchmeasurements are bedeviled by the Earth’smuch more massive atmosphere. Dollfusmade measurements at the Pic du MidiObservatory at an altitude of 2,877 metresin the Pyrenees. Greater altitude reducedfurther the effect of the Earth’s atmosphere,so he ascended by balloon into thestratosphere to make further measurements.
The outcome of his and others’measurements, predominantly at infraredwavelengths, was that the atmosphere ofMars contained a few millibars of carbondioxide (CO2) and a few hundredths of amillibar of water vapour. Oxygen (O2) was
undetectable, but homonuclear diatomicmolecules have very weak spectralsignatures in the infrared. Also, there’s a lotof O2 in the Earth’s atmosphere that wouldeasily mask a Martian signal. The same istrue of nitrogen N2. But N2 was chosen tomake up nearly all of the 80-120 millibarspresumably because unlike O2 it does notrequire an extensive biosphere, and alsobecause nitrogen is an abundant elementthat, for example, comprises 77% of theEarth’s atmosphere.
The white clouds are usually sparse andshort-lived. The more extensive polar hoodin the winter hemisphere lasted for manyweeks. Both types were presumed to consistof tiny crystals of water ice. Small isolatedwhite clouds were thought to mark mountaintops, such as one called Nix Olympica.There were also yellow clouds, mentionedearlier, extensive, sometimes to the extent ofcovering the whole planet and lasting fromdays to weeks. They were surely fine dustraised from the deserts by strong winds.Finally, there are high altitude thin hazes,called blue clouds, presumed to consist oftiny crystals of water ice, perhaps carbondioxide crystals too (dry ice).
So, how does the pre-Space Age picture ofMars measure up to our current knowledge?
Mars, August 1956, photographed byR.B. Leighton (north at top).
Right: Audouin Dollfus (at anadvanced age) about to ascend
by balloon to the stratosphere.
Pic du Midi Observatory,altitude 2,877 metres in
the French Pyrenees.
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Martian topographyThere was little evidence of Martiantopography before the Space Age. Isolatedwhite clouds were thought to mark mountaintops, such as Nix Olympica. As this article isabout Mars before the Space Age, I presentonly a brief summary of what we now knowabout the Martian surface.
The many images from flybys, orbiters, andlanders, show that the Martian surfaceconsists of two quite different hemispheres,the ragged boundary being inclined atabout 30° to the equator. The southerlysurface is peppered with impact craters,indicating a surface of age greater thanthree billion years. There are large cratersand small craters, but none very small—these have been weathered away. Abundantin this hemisphere are channels of variouswidths, lengths, and complexity, widelythought to have been carved by liquid watermore than three billion years ago, early inMars’s 4.6 billion year history.
The northerly surface is mostly fairly flat,with few impact craters, indicating youth. Butit does have the most dramatic topography.This includes a huge rift valley system, VallesMarineris, about 4,000 km long, up toseveral hundred kilometres wide and up toeight kilometres deep.
There are two broad domes, the largerbeing the Tharsis region, which bearsseveral shield volcanoes (from theirresemblance to a warrior’s shield). Thelargest of these is Olympus Mons, the largestshield in the Solar System and possiblydormant rather than extinct. It is about 550km across and rises to 25 km above theadjacent plains. It is at the location of thepre-Space Age Nix Olympica.
Life on MarsBefore spacecraft started to arrive in 1965(Mariner 4) it was still considered a possibilitythat the dark areas were vegetation. From1965 this was thought unlikely.
Mars was thought tobe devoid of life.However, within a fewyears this pessimistic
view changed, with the discovery, notedabove, of ancient channels that seemed tohave been carved by flowing liquid water,and gulleys on the sides of impact cratersand channels indicating contemporaryoutbursts of liquid water presumably fromreservoirs at no great depth.
Then there is methane gas (CH4) detectedin the early years of the noughties from Earthand also by the Mars Express Orbiter. Eventhough the level is only a few parts perbillion, methane is destroyed so rapidly in theMartian atmosphere that a steady source isrequired. Whether this is geological, orsubsurface methane-generating microbes(methanogens), is still an open question.
The current view is that there might be tinyfossils of life that lived in the first billion yearsof Mars’ 4.6 billion year history, when Marswas warmer and wetter than today. In anynear-surface liquid water reservoirs there justmight be microbes and tiny multi-celledorganisms living today.
So that’s it. You’ve surely noticed that I’vesaid almost nothing about mechanisms.That’s for another article as long as this one.
*The bright area material is thought today to be an erosional product of the dark area material.
Left: Some Martian valleysappear to have beenproduced by flowing water.
Below: Olympus Mons, a shield volcano on the Tharsis Bulge inthe northern hemisphere, possibly extinct. It is about 600 km across
and rises to about 22 km above its surroundings. NASA / JPL.
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Valles Marineris, in Mars’northern hemisphere, over
4,000 km long, 200 kmwide and up to 7 km deep.
It’s a stress fracture(NASA/JPL).
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India’s first mission to the Red Planet
Space Exploration
THE Mangalayaan mission is
India’s first attempt to send a
satellite to Mars. Mangalayaan
(Hindi, meaning ‘Mars craft’)
launched on the Polar Satellite
Launch Vehicle from Andhra
Pradesh in India, and will reach
Mars in September 2014.
Mangalayan’s main aim is to
develop the technologies
necessary for an interplanetary
mission, including the manoeuvres
needed in Earth and Mars orbit
and deep space communications.
Some of the instruments have a
heritage from Chandrayaan-1, the
Indian lunar satellite, as does their
deep space network.
Mangalayaan will study the
Martian surface and atmosphere,
look for methane and measure the
deuterium-to-hydrogen ratio,
which helps to understand Mars’
water loss process.
Impression of Mangalayaan in
orbit around Mars as it passes
over Ganges Chasma, a huge
deep canyon (named after
India’s River Ganges) that is
thought to have been formed by
catastrophic flows of water and CO2 in the distant past.
Graphic by PG (based on Google Mars / NASA / ISRO).
MARS orbiters Mars Express,
Mars Odyssey, Mars
Reconnaissance Orbiter and Mars
Global Surveyor have been used to
identify the remains of
supervolcanoes on Mars.
Some supervolcanoes have been
identified on Earth—Glencoe and
Yellowstone Park, for example—
and now the Arabia Terra on Mars
is proposed as a candidate area for
supervolcanoes.
When a supervolcano erupts, the
whole area gets involved with
many eruptions, vents and
fissures, and afterwards the whole
landscape falls back into the void,
producing a large caldera.
The deep scars in the Hebes
Chasma were formed when the
Tharsis region swelled up with
magma in the first billion years of
Mars’ history.
Mars Express has shown that an
eight kilometre deep trough, 315
km long and 125 km wide, was
formed. It is near to Valles
Marineris and just as deep.
There is no other canyon quite
like Hebes Chasma; it has a flat-
topped mesa in the middle of the
canyon and a horseshoe-shaped
chunk has been taken out of one
side of the mesa, where material
slumped down onto the valley
floor.
The minerals detected in the
canyon have been formed in the
presence of water, suggesting that
the canyon might have been
flooded for some time in its
history.
Inset, right: Hebe Chasma,
imaged by the High Resolution
Stereo Camera (HRSC) on board
Mars Express. Image: ESA.
Hebe Chasma (immediately right
of this caption) lies to the north of
the Valles Marineris. Graphic by
PG (Google Mars / NASA).
Hebe Chasma—a
Martian supervolcano?
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HELEN WALKER reports onastronautics, spaceflight and
space exploration
CURIOSITY has started to cause
a bit of a problem by failing to
detect methane on Mars!
Curiosity has been sampling the
atmosphere in Gale crater for a year
and has found no trace (less than 1.3
parts per billion by volume) of
methane. The Tuneable Laser
Spectrometer was used, and this
upper limit is around six times
lower than previous satellite and
Earth-based telescope estimates.
Mars Express
reported the detection
of methane several
years ago, in one
particular area and
maintained this was
a seasonal, geological
phenomenon.
Many people would
like methane to be
found, as evidence of
biological activity, but
it could be deposited by
comet or asteroid impacts
as well as by geological
activity. Hopefully, NASA’s
MAVEN, ESA’s Trace Gas Orbiter
or Mangalayaan will do better.
Mars news roundupMethanemystery
CURIOSITY has been more
successful with water detection,
finding a surprisingly large
amount—when it heated a small
pinch of soil from Rocknest in Gale
crater, there was around two percent
by weight of water in the sample,
much more than might be expected.
This means an astronaut could heat
around one cubic metre of soil and
get around ten litres of water—well
worth the effort. The sample also
gave off a lot of carbon dioxide, some
chlorine and also oxygen (similar to
that found by Phoenix in the High
Arctic region).
Another sign of the water-rich
ancient history of Mars comes from
one of the rocks identified early in
Curiosity’s mission. An unusually-
shaped pyramid rock was found (and
given the name Jake Maltijevic, after
a NASA engineer) and now the rock
has been identified as one not seen
on Mars before. It is a mugearite,
which means it is magma which has
crystalised in the presence of water,
and mugearite is found on islands
and rift zones on Earth.
Watersuccess
Above: Mars Express’ methane
measurements for Mars’ northern
summer. Image: ESA.
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ESA’s Automated Transfer Vehicle
(ATV-3) has been and gone.
Weighing 20 tonnes at launch and
delivering essential supplies to the ISS,
ATV-3 (named Edoardo Amaldi) has re-
entered the atmosphere over the
southern Pacific Ocean and burned up.
All the manoeuvres from launch to re-
entry were done autonomously, but
with close surveillance from the ground.
While at the ISS the ATV was
powerful enough to move the ISS to a
higher orbit, or move out of the way of
space debris, and regularly adjusted the
altitude to compensate for the
atmospheric drag the ISS experiences.
ORBITAL’s Cygnus freighter arrived atthe ISS on its demonstration flight.
There had been software problems, but
a patch was uploaded while the
freighter floated 2,000 km away
from the ISS, and a week later
than planned, it was allowed to move in
close to the ISS. It was grabbed by the
robotic arm, and moved to the Harmony
module allowing the astronauts to
unload it. After unloading, Cygnus left
the ISS to be destroyed as it re-entered.
SPACEX uses the Falcon rocket to
supply the ISS using their Dragon
module, and they have now launched
their Falcon 9 rocket (from Vandenberg
Air Force Base) which has several
modifications to boost performance. One
special new development was an
attempt to avoid destroying the rocket
on re-entry. After the first stage
separated, it fired its three engines
again to slow its descent, and then fired
a fourth engine to slow the descent
further. It lost stability and so landed
harder than they had hoped, but this
was a promising start to a new phase of
rocketry.
THERE are well-developed plans by
a company called UrtheCast to put
two cameras on the Russian part of the
ISS, looking at Earth, a high definition
still camera and a medium resolution
video camera. The High Resolution
Camera, supplied by RAL Space and
EVC, has passed its first acceptance
test and has been shipped to Russia to
join the other camera for the next stage
of acceptance testing.
ON 9 July astronaut Luca
Parmitano became the first
Italian spacewalker. An hour and
a half into his EVA outside the
International Space Station (ISS),
Parmitano found his helmet
starting to fill with water1a
potentially disastrous situation.
He managed to return to the ISS
safely, although it did take two
people to get him out of the
spacesuit.
Extra tools have been shipped
to the ISS to help investigate the
problem.
When the Japanese astronaut
Koichi Wakata takes over as ISS
Commander in November, he will
have someone to talk to—
Kirobo, a 34 cm high,
Japanese-speaking robot
programmed to provide
emotional support. The biggest
challenge was to make the robot
compatible with operating in
space. It is an interesting idea to
help support people isolated over
long periods, and we all talk to
inanimate objects like computers
anyway (don’t we?).
If you would like to see
something completely
fascinating, catch the YouTube
video by Chris Hadfield, a
Canadian astronaut on the ISS,
who was asked by school-
children ‘what happens when you
wring out a wet towel in space?’.
I won’t spoil it for you, but it is
well worth watching.
PenetratorONCE upon a time, not so long ago,
there was a UK mission design
called Moonlite, which involved firing
penetrators to study the Moon’s surface
and interior, study moonquakes, and
act as relay stations for instruments
out of the direct line-of-sight to Earth.
This was shelved but the penetrator
idea is still alive and well, and being
tested on ice penetration in west
Wales.
Recently a 20 kg steel penetrator was
fired at a 10-tonne cube of ice, used to
simulate the surface of Jupiter’s moon
Europa. The penetrator hit the ice at
340 m/s and decelerated rapidly with a
huge plume of snow, but remained
intact. This is too late to be included in
the Juice mission, which will launch
for Europa in next decade but there are
plenty of other targets including Mars.
Getting even a short distance into the
ground or ice means sampling interior
material which has been shielded from
the harsh radiation environment. Since
the penetrators are relatively cheap, a
network of penetrators could deploy
sensors over a wide area and allow a
variety of terrains to be studied.
The instruments inside the
penetrator are protected by a
suspension system from a Torlon
polymer. There is work still needed to
provide electronics which can survive
the impact, and work at the very low
temperatures in the environments on
the Moon, Mars, Europa, Ganymede
and further afield.
Near-drowning in space
Looking distinctly trepidatious,
Luca Parmitano prepares for a
simulated spacewalk beneath
the waters of the Neutral
Buoyancy Laboratory near
NASA’s Johnson Space
Center, Texas. He is wearing
a training version of his
Extravehicular
Mobility Unit
spacesuit.
Image:
NASA /
ESA.
ISS activities
ATV-3, imaged from the ISS prior to
docking. Image: NASA / ESA.Space Exploration
p26 Popular Astronomy www.popastro.com November-December 2013
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YOU could be forgiven for not knowing the name John
Goodricke. He is not a widely publicised astronomer, even
among the astronomical community. However, his ground-
breaking work on variable stars ultimately led to us being able to
use Cepheid variable stars as ‘standard candles’ and thereby
allowing us to measure vast distances across the Universe.
Goodricke was born in the Netherlands but moved to England
when he was still a small child. As a youngster he contracted
scarlet fever which sadly led to him losing his hearing. His family
still wanted him to get a good education so sent him to a
specialised school, the Thomas Braidwood Academy, which
specialised in teaching deaf people. He later moved on to the
Warrington Academy in 1778.
When Goodricke had completed his studies he returned to his
family home in York and it was this move that brought him
deeper into the world of astronomy. He became friends with his
neighbour, Edward Pigott, whose father was a professional
astronomer and had his own observatory. Pigott had already
developed an interest in variable stars and actively encouraged
John to observe them too. After all, the more people making good
observations of particular stars the better, especially because so
few variable stars had been observed at that stage.
Goodricke studied two well-known stars: Delta Cephei and
Beta Persei, otherwise known as Algol the ‘Demon Star’. His
studies opened up a new pathway in astronomical observation
because he discovered that the magnitude (brightness) of both
these stars fluctuated over time.
On 12 November 1782 Goodricke wrote in his journal (every
good astronomer should keep a record of their observations):
“This night I looked at Beta Persei and was much amazed to find
its brightness altered... I observed it diligently for about an
hour... I hardly believed that it changed its brightness because I
never heard of any star varying so quickly in its brightness.”
Goodricke and Pigott calculated that the drop
in magnitude took place every 68 hours and 50
minutes (2.87 days) and the pair theorised that
this was due to a dark object orbiting the star.
We now know that Algol is orbited by another
star—an eclipsing binary system.
Goodricke was only 19 years old when he
presented his monumental findings to the Royal
Society, a phenomenal achievement and the
crowning glory of his life. Elected to the Royal
Society in 1786, just two weeks before he died
aged 21, he achieved much in his short life—
even more impressive considering the prejudice
that he would have faced at the time for being
deaf. Who knows what else he might have
accomplished?
So the next clear night, take a look at Algol or
Delta Cephei (charts can be found on the
Variable Star Section’s Web pages at
www.popastro.com/variablestar/ and spare a
thought for the brilliant John Goodricke, an
astronomer who demonstrated that a disability
cannot stop you from doing what you love.
Astro pages compiled byGEORGE FORD andELIZABETH PEARSON
Young StargazersFamous astronomers
John GoodrickeTamer of the ‘Demon Star’
By David Scanlan
Born: 17 September 1764, Groningen, Netherlands
Died: 20 April 1786, York, England
Famous for observations of variable star Algol
Algol (Beta Persei) goes
through a regular cycle
of brightness changes.
Every 2d 20h 49m, over
a period of around ten
hours, it drops from
magnitude +2.1 to
+3.4—changes easily
monitored with the
unaided eye. The cause
is a large, dim
companion orbiting the
bright primary star,
periodically eclipsing it.
1: Algol at minimum.
2: Algol brightest.
3: Slight drop in
brightness (not detectable
visually) as companion
moves behind primary.
Graphic: PG.
November-December 2013 www.popastro.com Popular Astronomy p27
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IN June 2011, my wife and I went on
holiday to Norway and spent two
weeks above the Arctic Circle (latitude
66½ degrees north). We saw the Sun
24 hours a day, apart from one night
when it was partially obscured by the
Moon!
In the far north the Sun never sets in
the summer. The Earth spins once on
its axis each day. During daytime your
part of the world faces the Sun and
when you’re facing away it’s night. The
Earth’s axis isn’t at right angles to its
orbit—it’s tilted by 23½ degrees, and
its position is fixed in space, always
pointing towards Polaris (the North
Star). So, the amount of daylight you
get depends upon how far north or
south you are from the equator (your
latitude).
At different times of year different
parts of the Earth will be angled
towards the Sun, meaning that the
length of a day depends upon the time
of year as well as your latitude. If it’s
mid-summer in the Northern
Hemisphere then the North Pole is
tipped towards the Sun. If you are
within the Arctic Circle at this time,
then the Sun won’t set below your
horizon—you’ll get 24 hours of sunlight
a day! The further north you go the
longer this lasts. From northern
Norway the Sun is above the horizon
from mid-May to mid-July.
While we were in Norway we were
able to enjoy mountain walks in broad
daylight all through the night!
In the winter though the Earth
moves around to the other side of its
orbit so the North Pole is facing away
from the sun. This means you get 24
hours of darkness each day in the
winter but that’s great if you’re looking
at the Northern Lights. This year is a
great year to see the Northern Lights
as the sun is at a ‘solar maximum’
meaning the Northern Lights will be
even brighter than usual.
Solar eclipses happen when the Moon
gets between the Sun and Earth,
blocking our view of the Sun (either
partially or fully).
When we saw the midnight eclipse in
Norway the Sun was low. My wife took
several photographs of the event, but
it’s not a very sharp image because of
the glare of the Sun. The bottom of the
Sun was behind a hill and the top of
the Sun was eclipsed by the Moon so
all you can see of the Sun is two bright
spots. You can just about make out the
‘dent’ caused by the Moon in the
photograph. The clouds in front of the
Moon were bright as they were lit from
behind by the light of the Sun.
As an added bonus on that holiday,
there was also an eclipse of the Moon.
This happens when Earth gets
between the Sun and Moon and the
shadow cast by our planet darkens the
Moon; its red colour during a lunar
eclipse happens because Earth’s
atmosphere scatters the blue light but
lets faint red light through.
Unfortunately that event was
completely clouded out!
A partial eclipse of
the midnight SunBy Simon Cran-McGreehin
Above: Earth’s axis is tilted at an angle
of 23½ degrees to the ecliptic plane (its
orbit around the Sun). This means that
at certain times of year there are places
which are always tilted towards the
Sun and it’s always daytime.
Graphic: Simon Cran-McGreehin.
Young Stargazers
Above: The eclipse in progress. The
Sun is mostly blocked by a hill with
the Moon just covering the top. The
picture on the right shows you what is
going on more clearly. Image: Simon
Cran-McGreehin.
Did you know? The beauty of the total solar eclipse
is due to a pure fluke of the cosmos.
It just so happens that the Sun is
about 400 times the size of the Moon,
but also 400 times further away. When
Earth, Moon and Sun are in precise
alignment the Moon perfectly overlaps the Sun and its
dark shadow just
touches a small part of
Earth’s surface.
Jargon buster
Northern LightsOtherwise known as the Aurora Borealis, the
Northern Lights are caused when strong winds
of energetic particles from the Sun are funneled
down onto the Earth’s north polar region by its
magnetic field. The particles hit atoms in the
atmosphere, making them glow. This also
happens over the southern magnetic pole,
causing the Southern Lights or Aurora Australis.
p28 Popular Astronomy www.popastro.com November-December 2013
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Dark matterHelp! I don’t understand ...
Dark matterIF we were completely honest
we’d end this article right here
by saying ‘No, nor does anyone
else!’ But at least we can talk about
why astronomers think there is
such a thing as dark matter, and
what it might be.
Curiously, there is a direct link
with the previous Help! article,
which was all about the
satellite orbits. That
article showed how
the time that a
satellite takes to
orbit Earth
(the orbital
period)
depends
on how
high
it is.
Actually,
there is
another factor as well and that is
the masses of the objects involved.
Compare Earth and Moon with
Jupiter and Io, for example. Io and
the Moon are roughly the same
diameter and mass, and orbit
roughly the same distance from
their parent planet. While the Moon
takes 27 days to go around Earth,
Io takes only 42 hours to go around
much more massive Jupiter.
The more massive the object (or,
to be picky, the greater the
combined masses of the two
objects) the quicker the orbital
period.
The same applies to stars orbiting
each other as well, which is why
astronomers can work out the
combined masses of double stars by
measuring
their orbital
periods, even
though the stars
may be hundreds
of light years away
from Earth. On a larger
scale still, it applies to the
movements of stars around a
galaxy and even galaxies in a
cluster of galaxies… and it is here
that the trouble starts.
The first signs were noticed as
long ago as the 1930s when
astronomer Fritz Zwicky realised
that galaxies in clusters were
moving much faster than they
ought to, as if they were moving
around a more massive cluster
than the visible galaxies alone
suggested. Their speed meant they
ought to fly off in all directions
rather than move really fast in an
orbit. Some unseen mass was
holding the clusters of galaxies
together.
Astronomers then found that the
same applied to stars, which all
seem to orbit their galaxies at
about the same speed, no matter
how far they are from the galaxy
centre. This meant there had to be
a lot more mass distributed
throughout the galaxy than was
estimated by looking at the number
of stars alone.
Astronomers started talking
about the mystery of the missing
mass—and there’s a lot of it! On
average, there is about six times
more gravitational attraction than
there is detectable matter.
What could it be?Now you might say ‘It’s obvious, it’s
black holes’. So astronomers have
been searching for these unseen
black holes by looking for their
effects on the light from distant
stars. If a black hole goes in front of
a distant star, its gravity will act as
a lens so there will be a sudden
apparent flare. Thousands of stars
have been monitored for such
flares, but the black holes just
aren’t there. In fact, the search also
rules out other possibilities such as
‘rogue planets’ plus other dark
objects like brown dwarfs.
So what about smaller things,
such as particles? Are there just
more, or heavier, particles than we
know about? Big Bang theory
successfully predicts how elements
form, but only comes up with the
same amount of matter that we
actually see. Astronomers conclude
that whatever makes up dark
matter, it isn’t the same stuff that
makes up stars and planets (and
us). That just leaves something
unknown—something with mass
but doesn’t interact with the rest of
the Universe.
A possibility is some kind of
`Weakly Interacting Massive
Particles,’ (WIMPs) that the likes of
CERN have not yet been able to
detect. Alternatively, maybe our
theories of gravity or quantum
mechanics (the way particles
interact) need to be modified. Right
now, no-one really knows how the
whole problem of dark matter will
be sorted out. But it’s the sort of
investigation that could lead us to
understand far more about the
structure of the Universe. And who
knows where that could lead?
by Robin Scagell
Spiral galaxies such
as M64, shown in this
Hubble image,
contain visible stars,
gas and dust. In
addition there is dark
matter, betrayed only
by its gravitational
pull on the visible
matter. Image: NASA.
Young Stargazers
November-December 2013 www.popastro.com Popular Astronomy p29
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What is ESTEC?ESTEC is ESA’s European Space
Research and Technology Centre,
based in the Netherlands. It is the
technical heart of ESA’s space
missions where most ESA missions
are born, developed and tested before
flying into space. The tests check that
the satellite won’t be damaged during
launch or when it’s in space. The tests
at ESTEC expose the satellite to
severe shaking and tremendous noise
to mimic launch, and to extreme
heating and cooling cycles for weeks
on end to represent the harsh
conditions in space. Testing goes on
for months until ESA is convinced
that the satellite is capable of
performing well for the whole of its
planned lifetime.
What’s your role?I’m the Space Science Editor, which
means that I write most of the news
stories that you see on the space
science section of ESA’s website
www.esa.int/science. These stories
cover the exciting results from all of
our space missions. There are roughly
20 space missions that I write news
articles about, some of which have
been in space for ten years or more,
while others are still being tested at
ESTEC. The missions cover the
Sun and planets in our own
Solar System, to stars and
galaxies across the
Universe.
Other editors at
ESA are in charge
of writing about
other aspects of
space exploration,
such as observing
our own planet,
astronaut missions
to the International
Space Station,
rocket launches, and
telecommunications.
I also write our ‘Space Science
image of the week’, which showcases
images from our missions—both
brand new, never-before-seen images
of the stars and planets and also
really stunning images from our
archives. One week it might be a new
Cassini image of Saturn and the next
it might be ExoMars being tested in
the ESTEC test centre. Check the
space science page each Monday for a
new image.
What have been
the most exciting
stories you’ve
worked on?When I first started at ESA
more than a year ago I was
lucky to be invited to go to
Svalbard with the Venus
Express science team to
report on the transit of
Venus—to watch Venus
pass in front of the
Sun—an event that
won’t happen again this
century. Svalbard is an
island located about
halfway between
mainland Norway and
the North Pole, and
when we visited
in June, it was
daylight all
day—the Sun
never set! It was
one of the few
places in the
world where
you could
watch the
entire transit
from beginning
to end, and we
only had a few
interruptions from
clouds.
One of our more recent stories was
the grand unveiling of the most
precise image of the Cosmic
Microwave Background (CMB)—the
relic glow of the big bang that created
our Universe nearly 14 billion years
ago. ESA’s Planck space telescope has
been making sensitive observations of
this radiation since
it launched in
2009.
After years of painstaking detective
work sifting through all the data,
Planck scientists finally showed the
new ‘baby photo’ of the Universe in
March 2013. There was a lot of media
coverage after ESA released the
image, and the story made it to the
front page of the Financial Times, the
New York Times and many other
newspapers across the world. It was a
very proud and exciting moment for
everyone involved in the project.
What’s it like to work at the
European Space Agency?Former SPA Chief Stargazer Emily Baldwin drops by to tell us all about
working as space science editor at ESA’s ESTEC in the Netherlands, and the
exciting space missions that we should all be watching
Emily
views the
transit of
Venus using
‘eclipse
glasses’.
Despite being
‘night time’
it was sunny,
but still very
cold!
Planck’s
CMB
image will
help scientists
learn more about
the development of the
Universe. Image: ESA.
Young Stargazers
p30 Popular Astronomy www.popastro.com November-December 2013
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In June 2013 ESA’s Mars Express
mission celebrated ten years since
launch. The mission has been
observing all aspects of Mars’
environment, from below the surface
to its atmosphere and beyond to its
two moons Phobos and Deimos.
Perhaps it is best known for the
stunning 3D images it takes of the
Martian surface, highlighting
different environments from volcanoes
to ice caps to valleys that may have
been carved by water. To mark the
mission’s 10th birthday, scientists
presented a new global mineral atlas.
These include minerals that formed
only in the presence of water and
minerals formed during volcanic
eruptions, so plotting where and how
old they are helps trace the planet’s
history. The maps will also be used to
help choose the landing sites of future
missions, such as ESA’s ExoMars
missions that launch in 2016 and
2018.
If you enjoy looking at Mars then
take a look at ESA’s website each
month for a new set of images from
Mars Express. It’s always exciting for
me to see the new images and use my
planetary science degree to
understand what the pictures are
telling us about the planet, and then
share it with all of you.
Great things to comeThere’s always something exciting
happening at ESA but there are two
big missions coming up in the next
year that are particularly important
for space science. One is the Gaia
mission. It is equipped with a 1,000
megapixel (that’s a billion pixel
camera; for comparison my mobile
phone has a 5 megapixel camera) and
it will study a billion stars. Its goal is
to make the largest, most precise 3D
map of our Galaxy by precisely
charting the positions, distances,
movements, and changes in
brightness of the stars. It is also
expected to discover new exoplanets,
asteroids and failed stars called
brown dwarfs.
Meanwhile the Rosetta mission
finally reaches its destination in 2014.
The spacecraft launched in 2004 and
has passed three times around Earth,
once around Mars and has flown by
and imaged two asteroids, before
going into deep space hibernation in
July 2011. In January 2014 Rosetta
will get a wake-up call as it draws
closer to its final destination: Comet
67P/ Churyumov-Gerasimenko (I’ll
need to practice how to say—and
spell—the comet’s name!).
The mission will be the first to
follow a comet as it makes its journey
around the Sun, and watch as its icy
surface is warmed up by the Sun. It
will also be the first mission to land a
probe onto a comet’s surface. There it
will study the comet’s surface, helping
scientists to learn more about these
‘dirty snowballs’ that could have
helped give Earth its water billions of
years ago.
Life in the
NetherlandsIt is fantastic to live in a new country.
Every day I interact with colleagues
from all over the world, so I learn a
lot about different cultures and
languages. Although everyone speaks
English at work, I’m trying to learn
Dutch. My partner also moved to the
Netherlands with me and we have
enjoyed exploring other parts of
Europe that are now a lot closer and
easier to get to than if we were in
England. But it’s still easy to visit our
friends and family in England, and
we were pleased to see lots of our
astronomy friends—including our
SPA friends—at AstroFest last year.
Where is ESA?ESA has sites all over Europe:
1. ESA’s Headquarters are in Paris, France.
2. ESTEC, the European Space Research and Technology Centre, is ESA’s
largest site, based in the Netherlands. Here satellites are tested before
they go into space.
3. ESOC, the European Space Operations Centre, is in Darmstadt,
Germany. ESA spacecraft are controlled from ESOC during their missions.
4. ESRIN, the Centre for Earth Observation, is in Frascati, Italy
5. ESAC, the European Space Astronomy Centre, is ESA’s centre
dedicated to space science and astronomy, and is based near Madrid,
Spain.
6. EAC, the European Astronaut Centre is in Cologne, Germany, and
trains Europe’s astronauts, including the UK’s Timothy Peake.
7. ESCAT, the European Centre for Space Applications and Telecoms,
recently opened in Harwell in the UK.
7 2
6
1 3
4
5
Find out moreESA Space Science: www.esa.int/Our_Activities/Space_Science
Space Science Image of the Week:
www.esa.int/Our_Activities/Space_Science/Image_of_the_week_archive
Take a virtual tour of ESTEC’s test centre:
esamultimedia.esa.int/multimedia/ESTEC/virtualtour/
Download space science mission posters:
www.esa.int/Our_Activities/Space_Science/Wallpapers
ESA homepage: www.esa.int
Emily’s ESA
portrait.
Image:
ESA.
Young Stargazers
November-December 2013 www.popastro.com Popular Astronomy p31
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Astronomy Diary
2014 (Kickstarter
project)Discover the mysteries of the Universe
By Kate and Julian
www.astronomydiary.co.uk
Softback, 66 pp / £10 (to pledgers)
This is a first for the Reviews section of
Popular Astronomy—a review of a book
yet to be published, and may never be
published unless it receives a certain
amount of funding from potential
buyers.
This new astronomy book was
recently launched on crowdfunding
website Kickstarter. Aimed at
promoting naked eye observing, the
project, if successful, will fund the
publication of a novel pocket-sized
astronomical guide—Astronomy Diary
2014.
Described as a ‘What’s On’ guide for
the night sky, Astronomy Diary 2014
will give weekly recommendations for
observations and must-see celestial
events.
The authors are two Londoners, Kate
and Julian (whose surnames I couldn’t
find) who had trouble
dedicating time to
their passion for
stargazing.
What
began as
their
personal
plan to list and
view the must-
see celestial events
of 2014 could now end
up in the hands of
astronomers across the
country, if the couple’s
Kickstarter project gets funded.
Astronomy Diary 2014 aims to spark a
lasting interest in astronomy in both
adult and young newcomers to the
hobby, but could also act as a handy
aide to more experienced observers. It
features weekly recommendations for
the most popular objects visible to the
naked eye or with binoculars. It
includes transient events such as
meteor showers, conjunctions and
eclipses, the positions of planets and
phases of the Moon along with
established sights such as
constellations, famous star clusters,
galaxies, nebulae and double stars. Key
historical dates related to astronomy
and space exploration are also included.
Being a diary, space is left for the
reader to record their own notes and
observations of celestial events.
It all looks a very worthwhile
project and from the
material posted online
(see websites below) it
looks very nicely done and
well-presented. Kate and
Julian have until 14 November to
fund their project and make their
idea into reality.
For more information about this
Kickstarter project, see:
www.kickstarter.com/projects/15178340
76/astronomy-diary
Official website:
www.astronomydiary.co.uk/
Contacts:
Peter Grego
Please note that I have no vested interest
in this book, nor am I a pledger, but I
will be keeping an eye on its progress.
We will feature a review of the book
itself in the January-February issue of
Popular Astronomy if it comes to
fruition.
The Cambridge
Photographic
Moon AtlasBy Alan Chu, Wolfgang
Paech and Mario Weigand
(translated by Storm Dunlop)
Cambridge University Press
ISBN: 978-1107019737
Hardback, 192 pp / £35
As a keen lunar observer, I’m
always excited when a new book
about the Moon is published,
especially when that new book is
a lunar atlas.
Printed in large format
(measuring 1.8 × 25 × 33.8 cm)
this latest attempt to illustrate
the wonders of our natural
satellite’s visible hemisphere is
nothing but spectacular.
Photographic coverage of the
Moon’s near-side is achieved in
the illustration of 68 regions with
388 different images. These
regions are loosely delineated and
centred around certain major features,
with attention drawn to a variety of
interesting formations. Because of this,
the atlas isn’t as as easy to search
through as, say, Rükl’s neatly-defined
Atlas of the Moon; nor does it show all
the sections under a variety of
illuminations, like Hatfield’s
Photographic Lunar Atlas. But this isn’t
a problem, as key annotated images
showing the areas depicted are given at
the front and back of the book.
All the images were secured by the
authors, each of whom is a skilled lunar
CCD imager. Chu more than
successfully images the Moon from his
balcony overlooking an unfeasibly
vertically urban Hong Kong using a
10-inch Newtonian, while both Paech
and Weigand do their astronomy from
Germany, using a 6-inch refractor/14-
inch SCT and 11-/14-inch SCT
respectively.
Opinions on a selectionof astronomy books and
productsReviews
p32 Popular Astronomy www.popastro.com November-December 2013
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Reviews
There’s more text to this atlas than in
the Rükl or Hatfield atlases. The
Moon—an Introduction makes up first
26 pages. Here the authors attempt an
summary of the Moon as a world, a
potted history of lunar geological
processes (with some reference to older
theories), a discussion of the Moon in
space and information and advice on
lunar observing with particular
emphasis on CCD imaging. All of this is
very well-illustrated with images by the
authors along with NASA photographs.
The sheer quality of the images, many
of which are so good as to be presented
very large without a trace of pixellation,
really makes this book stand out from
other Earth-based photographic Moon
atlases.
Although many of the images are
overlain with labeling, the style in
which this has been done makes the
text, dots and lines completely
unobtrusive—that’s a great
accomplishment and I take my hat off
to the graphics people at CUP.
The meat of this atlas is the 68 near-
side sections (plus one grudging
single-page section on the far-side at
the end!), which take up 154 pages.
Unfortunately there are no page
numbers in the atlas part, even
though their inclusion would have
been very handy and in my opinion
wouldn’t have detracted from the
design. Arranged in an order that
generally follows the progress of the
lunar day, they are all accompanied by
notes explaining various features in
the images, some obvious and others
les grand but of high interest.
This atlas’ meat is exceptionally
tasty, and one feels almost guilty for
indulging in it, so beautiful are the
images. It’s wonderful to view so many
familiar features—craters, mountains,
domes, ridges, faults and valleys—in
such sumptuous detail. It’s the
nearest thing you can get to actually
seeing them for real under good
conditions (and to do that you need a
telescope). I would say that the
minimum level of lunar detail in the
lowest-resolution image in the atlas
equates to that visible with the acute
eye at the high-magnification ocular of
an 8-inch telescope, and the best ones
show detail that is unattainable
visually with an amateur instrument.
Most of the images are in black and
white, or seem to be tinted very,
slightly, almost imperceptibly brown
(to my eyes), while some are in colour
(a realistic colour without saturation,
matching the eyepiece view). The
finest of the colour images is
undoubtedly that of the Aristarchus
region (section 58), showing a Wood’s
Spot of glorious raw Sienna and a
blue-grey region intruding into it from
Aristarchus.
The most obvious error is the
transposition of the images featured in
the lower part of sections of 41 (South
Pole) and 54 (Sinus Iridum); this
unfortunately sees a wrinkle ridge in
Mare Imbrium identified as the South
Pole and the South Pole identified as
Sinus Iridum.
The geological descriptions are very
good, but I have a few bones of
contention. For example, on p15 it is
stated that the Iridum basin was
formed by impact before the Imbrium
basin; the superposition of the former
by the latter makes this very unlikely. I
was not convinced by explanations of
several other features in the atlas. For
example, craters with smooth-looking
flat floors aren’t all lava-flooded; many
of them are more likely covered with
impact melt (as described in section 1).
This goes for some other smaller craters
whose smooth floors are likely wrongly
ascribed to lava. In the case of the
ancient crater Newcomb C (section 3)
the floor is more likely smooth because
of erosion and overlying ejecta deposits.
It is however true that many larger
craters do have lava flooded floors, as
they ruptured the crust sufficiently to
allow mantle material to rise to the
surface. I’m also reluctant to accept that
lunar geologists believe that the inner
rings of small double-walled craters like
Hesiodus A (p21, section 46) are
attributable to the intrusion of highly
viscous magma in an annular zone.
With respect, I think that this is fair
criticism, because although I’m not a
qualified geologist (let alone planetary
geologist), neither are the authors.
Historically, lunar geology has been
coloured by both amateur and
professional speculation, and I dare say
my own work The Moon and How to
Observe It (which the authors kindly
mention in Further Reading and
References) can be criticised in like
manner!
I congratulate the authors on
producing this atlas. It is a beautiful
book that now takes a proud place on
my bookshelf, and I will probably
consult it often. I thoroughly
recommend it to every astronomer
(amateur or profesional) with an
interest in the Solar System.
Peter Grego
Revised and Updated Edition
By Ben Bussey and Paul Spudis
Cambridge University Press
ISBN: 978-0521141017
Softback, 317 pp / £35
In 1994 the NASA/DoD Clementine
mission gave us our first global
view of the Moon as it imaged the
surface in various wavelengths
from lunar polar orbit. This atlas
presents us with the UV-visual
results of that overview, tying it in
with the more recent Lunar
Reconnaissance Orbiter (LRO). Perhaps
it would have been better titled The
Clementine/LRO Visual Lunar Atlas.
The first section describes the Moon’s
geological history, plus a short history
of lunar science and exploration. The
atlas itself consists of 144 black and
white maps
compiled from
Clementine UV-
VIS imagery
covering the
whole lunar
surface, each
showing an
overhead view
of an individual
area. These are
presented in
two-page
spreads, along with a corresponding
map based on more LRO data/imagery
(the latter being a new feature of this
updated edition). First published in
hardback in 2004, this is a most
welcome revision and an essential for
any Moon fan. Peter Grego
The Clementine Atlas of the Moon
November-December 2013 www.popastro.com Popular Astronomy p33
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LettersThe Seeliger
Effect—on Earth as
it is on Saturn?I was intrigued to hear of the ‘Seeliger
Effect’ in Alan Clitherow’s Planetary
Section report (PA Sep-Oct 2013). The
apparent brightening of Saturn’s rings
around opposition sounds very similar
to an oft-reported terrestrial effect.
Many pilots, and the occasional
passenger, have noticed the effect when
flying over a field of grass or a prairie
full of grain. Looking directly away
from the Sun, the shadow of the plane
appears surrounded by a bright circle in
the corn a degree or two across.
There are two effects at play. The first
is the obvious effect that if one looks at
any illuminated object then you will see
more reflected light from straight on
than if looking from the side. This effect
is very small; for a one degree offset,
the loss of light is only 0.015% and at
six degrees the loss is still barely half a
percent. Hardly enough to be noticed by
the human eye. Think of the secondary
mirror in a reflecting telescope. In a
Cassegrain, a circular mirror turns the
light 180 degrees. In a Newtonian,
where the light is turned 90 degrees, an
elliptical mirror is used because a
circular one would lose 30% of the light.
The second, and more significant,
effect is believed to be shadowing.
When viewed straight on, all the
reflected light returns on the same path
on which it went in; an un-obstructed
path to and from each and every blade
of grass. When viewed from even a very
small offset, some of the light reflected
from the more remote grasses will be
intercepted by grasses nearer to the
observer. Hence the observer is looking
at a mixture of illuminated surfaces
and surfaces hidden in shadow. The
Seeliger Effect would seem to be the
same shadowing effect among the
particles making up the rings of Saturn.
Saturn is 9.25 times the mean
distance of the Earth and its orbit is
inclined at 2.5 degrees with respect to
Earth’s orbit. At opposition therefore,
calculations with the simple geometry
of sines and cosines show that the
sunlight will be diverted by anything
from 0 degrees (at either of the nodes
when Saturn is in the plane of Earth’s
orbit) to 0.29 degrees (when opposition
occurs with Saturn at maximum
declination above or below the ecliptic).
Even at quadrature, the reflected light
will be diverted by no more than about
6.0 degrees. Could a plot of intensity of
reflected light against diversion angle
tell us anything about the particle
density in Saturn’s rings?
A third mechanism, that of the corner
reflector, might be at play in the ring
particles; though not in a field of corn. A
corner reflector can be made from three
mutually perpendicular mirrors; the
inside corner of an empty box. Any
beam of light that reflects of all three
mirrors in sequence will be returned to
its source. This is the principle behind
the ‘eight-corner radar reflector’ that is
often flown from the masthead on small
fishing boats. A corner reflector can also
be made from a transparent solid of
sufficiently high refractive index; the
outside corner of a full box. Any beam of
light that gets into
the solid and then
undergoes total
internal reflection at
all three
solid/vacuum
interfaces in
sequence will also be
returned to its
source. This is the
principle behind the
red-plastic reflector
on a car or the clear-
glass ‘cat’s eye’ in
the road. Could some
of the material
forming Saturn’s
rings be a
transparent mineral
that forms crystals
with cubic-orientated
plane surfaces?
Brian M. Russell
Alan Clitherow replies:
The generally accepted explanation for
the Seeliger Effect is the ‘shadowing’ you
refer to. In simple terms the reflective
particles in the rings scatter light in all
directions; however, they also cast
shadows that are visible when they fall
on particles behind them. When viewed
from anywhere other than directly in
line with the light source these shadows
darken the overall visible picture. When
viewed close to opposition these shadows
are hidden behind the particles casting
them so the overall darkening effect of
the shadows disappears.
A similar effect can be seen when
comparing the brightness of the full
Moon with that of a first or last quarter
Moon. In general you would expect the
full Moon to be twice as bright as a
quarter Moon since the illuminated area
is twice as large. In fact it shines
noticeably more brightly as there are no
dark shadows cast by relief features to
be seen anywhere on the disc, shadows
that effectively cut the visible reflective
area of a quarter Moon.
Thinking about this from a slightly
different point of view, if the rings of
Saturn are made of randomly orientated
reflective particles then from any given
viewing angle one will see a number of
particles that just happen to be reflecting
sunlight towards us, and this light will
have been reduced by scattering off the
randomly floating particles that
intervene with that reflected light-path.
When the Sun is directly behind us and
the rings are directly in front of us any
aligned reflected path has the shortest
distance to travel through the
intervening particles resulting in the
minimum amount of light scattering;
more reflected light reaches us and the
rings appear brighter. This effect will be
smallest when the particles are equally
reflective in all directions and largest
when the particles have only a small
highly reflective face as found with
complex crystalline structures. This
would be particularly true of any
particles having 90-degree edge
reflectors within crystalline structures
(or allowing total internal reflection
within a refractive molecule) but I do not
specifically know of any such within
Saturn’s rings.
A variation on this approach involves a
‘coherent backscatter effect’ in which the
reflected light is enhanced at narrow
angles if the size of the scatterers in the
reflected light path is comparable to the
wavelength of incoming light and the
distance between scattering particles is
greater than a wavelength; the result, as
Your comments, views,opinions, news, stories,suggestions and poems
A surge in brightness appears on Saturn’s A ring
directly opposite the Sun from the Cassini
spacecraft. This ‘opposition surge’ moves across the
rings as the spacecraft watches. This view looks
toward the rings’ sunlit side from about 9°
below the ringplane. Image: NASA.
p34 Popular Astronomy www.popastro.com November-December 2013
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Letters
I understand it, is that the reflected light
bouncing back towards its original source
is coherent with the incident light and
there is no scattering or destructive
interference. I will confess to being at the
limits of my knowledge here and would
welcome an expert stepping in.
Variations in the orbital inclinations of
both Saturn and Earth will cause
variations in the overall amount of
brightening as you suggest, simply
because our viewing angle varies closer
to or further away from the direct line
between Sun and Saturn. However the
biggest factor must be the apparent
change in inclination of the rings as seen
from the Earth since the total reflective
area dramatically increases as the ring
angle increases; giving either brightening
effect more area to have an effect on.
As for the ‘circle of brightness’ around
an aircraft shadow when seen from that
aircraft: this is known as a ‘glory’ and is
something I have seen and photographed
a number of times. It can be understood
in the same terms as the shadowing
effect already described when the
illumination falls on a solid object. When
it falls on dispersed particles, such as
water vapour in a cloud, its cause is still
disputed but seems to involve either two
internal reflections interfering with each
other within a rain-droplet or bizarre
quantum tunneling effects whereby a
photon-wave passing close by, but
missing, such a droplet still imparts
some energy to it. In either case it
causes the reflected light to be changed
in frequency (rainbow effects) and
dispersed rather than concentrated. For
this reason I doubt it has much
application to the Seeliger Effect
arising from dispersed particles within
Saturn’s rings
Alan Clitherow
A close-up of the visor of Buzz Aldrin’s
helmet, showing the opposition effect
brightening the area around Aldrin’s
shadow. Image: NASA.
Nova Del 2013I sent this observation
into the SPA’s
Variable Star
Section, but I
thought you
might be
interested in
seeing it too.
It’s been a
while since I
have had
chance to do
much
observing, but
news of Nova
Delphini 2013
piqued my interest,
and I have been
fortunate to be able to
make a couple of observations. The
first was in the early hours of 18
August at 03h UT. At that point the
nova had faded slightly from its
original peak. Unfortunately, I’m not
very experienced at estimating star
magnitudes, but my very rough
estimate put it close to mag. +5.5. I
managed to make this supporting
sketch, from my second observation.
This was drawn
on 22 August at
21:41 UT, when the
nova appeared slightly
fainter still.
I think this is the first time I
have ever observed a nova, and it was
fascinating to imagine the process
that has taken place to result in this
incredible brightening.
I shall keep watching, as and when
I get the opportunity, and follow the
progress of this event.
Jeff Stevens
Stoke-on-Trent
Jeff’s observational drawing of Nova
Delphini 2013, made using
8×56 binoculars. North
is at top. The nova is
at the intersection
of the two lines,
with an
estimated
magnitude of
+5.7. The
brightest star
to the far left
is 29
Vulpeculae,
at mag. +4.8.
New brush
sweeps
cleanerMy new
Canon 600D
(18.7 Mp)
has a lot
more to
offer than
my 1100D
(12.2 Mp). It
can shoot 30
frames straight
off of a moving
subject and on
image stabilizer
automatically in several
configurations. Fantastic
resolution. You can open the display
screen and turn it round to any
position, or simply slot it into the back
and use it like one without that type of
hinged display.
I attach an image I took at 18:30 on
15 October over my garage, using a
Canon 300 mm lens lens and not a
telescope. The waxing gibbous Moon
was very bright and the starry sky was
brilliant. I stacked seven images in a
software program I have to take away
the blurring of the sky
background. No other
processing was
needed. I’m going
to try and get
all 28 phases
of the Moon
as a quick
project over
the months
ahead. It
only takes a
few minutes
each evening
to do some
snapshots.
John Fletcher
Mount Tuffley
Observatory,
Gloucestershire
Express yourself!Popular Astronomy welcomes
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November-December 2013 www.popastro.com Popular Astronomy p35
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The Moon
Recent observations. The short nights
of the late spring and early summer
generally lead to a lull in meteor observing
and a reduction in fireball reports. Night
time meteor rates do pick up in late July
however and reports of Aquarid /
Capricornid activity and of early Perseid
activity had been received from Graham
Winstanley and Alex Pratt by the time the
column was written in early August. Alex
noted in particular that he had captured
images of six Alpha Capricornids. Given
its low ZHR, this shower might not appear
very promising. However the meteors that
it does produce can be very memorable—
they are typically slow moving and often
have distinctive colours and long paths.
Perseids vs Geminids. Which meteor
shower is the best in terms of fireballs? An
article published by NASA in late July
made the claim that the Perseids are the
‘fireball champions’. This surprised many
experienced meteor observers as their own
experience was that Geminid meteor
watches produce a higher percentage of
fireballs. However, closer inspection of the
article revealed that it actually referred to
the total number of fireballs produced by
each shower. Although the Perseids
produced a significantly higher number of
fireballs than the Geminids did, this was
almost certainly merely a consequence of
the Perseids having a longer activity
period and therefore having more nights
to build up their total. The article can be
found at science.nasa.gov/science-
news/science-at-nasa/2013/26jul_perseids
Bright flashes. Flashing objects are
sometimes seen in the night sky. In some
cases the objects show repeated flashes as
they cross the sky. Aircraft are the most
common example. Some satellites also
produce regular flashes as they ‘tumble’
along their orbit and their solar panels are
periodically lit up by sunlight. Single very
bright flares can be seen from Iridium
communications satellites, but these also
show some motion during the flare. More
unusual are stationary flashes at a point
in the sky. Some of these will be head-on
meteors or strongly twinkling faint stars.
Others could merely be flashes in your
eyes (or more precisely random firings of
neurons in the optic nerve). There are
cases however that do not fit these
explanations in that they are seen at the
same point in the skies by observers
several miles apart.
SPA contributor Peter Meadows
highlighted an example in a recent issue
of The Astronomer magazine. His image
and another taken several miles away
both recorded the object. Had the flash
been from a meteor or from an aircraft
there would have been a small difference
in the object’s position against the star
background between the two images.
Since there was not, the object must
therefore be more distant. Peter suggested
that the most likely explanation was a
specular reflection (glint) from a satellite.
Tony Markham
Section reports
Since our report in the Sep-Oct issue of PA,
observational lunar drawings have been
made by Dale Holt and me. In addition, a
wide selection of lunar CCD images has
been submitted by Mike Brown, David
Finnigan and David Scanlan. If I’ve missed
anyone out, please let me know, as I receive
lots of lunar material from non-SPA
sources.
Our subject is the crater Hippalus on the
southeastern shore of Mare Humorum. My
observational drawing of sunrise over
Hippalus (made on 20 April) was featured
in the Lunar Section report of the Jul-Aug
issue of PA; this latest observation (shown
at left), was made on 14 October and shows
the feature at a slightly more advanced
illumination.
From its appearance, Hippalus is
evidently very ancient and has had
a chequered history. After its
impact formation it was subjected
to further impacts, producing its
oddly scalloped shape; its western
wall and floor was then flooded by
lavas from Mare Humorum. Once
this had solidified, crustal tension
around the mare edge produced the
arcuate rilles (known as the Rimae
Hippalus) that cut through
Hippalus’ floor and walls. There is
lots of fascinating detail in the area,
such as mountains and low ridges.
You can view a similar scene of
sunrise over Hippalus on 14
November and 12/13 December.
Peter Grego
View a scene of
crater catastrophe
Top: Sequential observation of Hippalus
made on 14 October at 20:45 to 22:20 UT
by Peter Grego (12-inch Newtonian).
Right: David Finnigan’s image of Mare
Humorum and Hippalus (with enlarged
detail above) taken two days later (12-
inch SCT, ZWO ASI 120MM CCD).
Odd flash probably
no point meteor
Observations, news and notes from the
SPA Observing Sections (all times UT)
Meteors
p36 Popular Astronomy www.popastro.com November-December 2013
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Occultations
It has been a quiet couple of months for
the section with no reports coming. That
being said, information regarding
occultations has been given out to those
requesting it.
For this coming period, November to
December, we have seven reappearances
and three disappearances (not including
the disappearance of Lambda Geminorum
at the Moon’s bright limb)—for a full
listing of occultation events see Sky Diary
on p44.
On 22 November, the magnitude +3.6
star Lambda Geminorum is occulted
(graphic shown at right). I have included
information for the disappearance at the
bright limb, which occurs less than an
hour before the reappearance at the dark
limb of the Moon.
The early morning of 24 November sees
the magnitude +5.4 star 60 Cancri
occulted by the 66% illuminated waning
gibbous Moon, as seen from London. The
north of the country will see an appulse.
The graze line for this event (shown on
the map here), running west to east, is as
follows: west coast of Eire, just north of
Belmullet, and across country to the east
coast of Ireland north of Ardglass. The
line crosses the Isle of Man to the west
coast of mainland UK just to the north of
Barrow-in-Furness, it travels across
northern England, north of Harrogate
and York, through Old Malton (Malton,
north Yorkshire) and then out to the east
coast at Flamborough Head. Anyone
south of this line will see a reappearance
of the star. If you require a more detailed
map of this grazing event, please do get in
touch and I can provide the Google Earth
file for you.
19 November’s two occultations will be
difficult observations due to the waning
gibbous Moon being 98% illuminated. As
mentioned in information on previous
events of this nature, try to keep as much
of the Moon out of the eyepiece as possible
and familiarise yourself with the region of
the Moon where the star is to reappear.
For those new to observing occultations
and not wishing to be up in the early
hours of the morning, the disappearance
of magnitude +4.3 Epsilon Piscium
behind the dark limb of the waxing
gibbous Moon on 11 December, should be
a good one to attempt (see graphic below).
Because the star disappears behind the
dark lunar limb, you will be able to
observe the star right up until it
disappears. It’s watching this type of
event that shows you that the Moon is
moving against the background stars, as
well as the Earth rotating causing them
to rise and set.
Another feature of occultations to watch
for is when a star doesn’t immediately
appear or disappear, such as in cases
where the star is a known double star.
The brighter star may disappear, leaving
the usually unobservable fainter
companion visible for a brief while.
Alternatively, the fainter star may
reappear from behind the dark lunar limb
before the brighter one. A number of
double stars have been discovered this
way.
Any observations of occultation events
are welcome, timed or not. If you require
further information please get in touch.
Mell Jeffery
Northern graze
The graze path of
60 Cancri on 24 November.
Image: Google Earth.
Section reports
Lambda Geminorum is
occulted on 22 November. Its
disappearance at the Moon’s
bright limb will prove difficult to
observe, but its reappearance at the
dark limb around an hour later will
be much easier to see.
The disappearance of
Epsilon Piscium on the
evening of 11 December
provides a good
introduction to
observing
occultations.
November-December 2013 www.popastro.com Popular Astronomy p37
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Report for June and July. The section
recorded a relatively low number of
observations during the period; this is
understandable with Saturn sinking into
the western sky and no other well-placed
planets to observe. However the period was
successful for two reasons. Firstly, the
proportion of visual observations increased,
revealing something interesting about
Saturn’s largest moon Titan. Secondly,
some new cameras and interesting
processing and imaging techniques have
produced better images of Saturn than
expected given the conditions.
Starting with visual observations, both
Alan Heath and Matthew Barrett sent
detailed reports despite what Alan
described as his ‘worst ever apparition’ of
Saturn due to weather. These reports give
estimations of the visual intensity of the
major visible bands, zones and rings, as
well as notes on the position and colour of
major moons, Titan of particular note in
this case. The intensity estimations were in
close agreement between the two
observers; there were obviously some
variations, but Matthew’s observation of 5
June and Alan’s of the 6th were almost
identical. Visual estimations are useful
when looking for variations over time and
for comparison with images. Both methods
of observation are very useful and I’m glad
visual reports are increasing.
One interesting point was Alan’s
estimation of the visual colour of Titan. On
10 June he recorded it as a creamy-yellow
colour whereas on the 6th it had appeared
a deep red. He acknowledges that the low
altitude of observation will play tricks with
observed colour, but noting no significant
changes in seeing conditions between the
two observations he was struck by the
colour change; certainly there was no big
change in elevation in four days. In order
to see if there was any obvious correlation
between colour and orbital position he then
plotted dated colour estimates taken from
both this year and 2012 against Titan’s
orbit. From this he suggests that Titan
seems least red when approaching its
farthest point to the west of Saturn. Alan’s
own records of estimations of Titan’s colour
date back to 1958 and he intends to look
closer at these to further investigate this
subject. Observations by NASA’s Cassini
probe indicate that there is a sound basis
for Alan’s observation. Any other reports or
observations on this topic are welcome.
Saturn remained the only object imaged
by section members—indeed it was pretty
much the only game in town during the
period. Section members contributing were
Mike Brown, David Finnigan, Martin
Lewis, Steve Norrie, Paul Crossland and
myself. Early June was well-reported with
multiple observations during a clear period
extending to the 10th.
With Saturn less than 27° high and with
strong winds in our own atmosphere
causing unsteady seeing, Mike Brown
compared the planet’s visibility through a
range of filters. Red and near infrared (IR)
light cuts through turbulence better than
green and blue light, especially blue which
gets scattered, dimming it considerably.
Mike’s images from 3 June compared
results through red, green and blue filters
on a monochrome camera with extra
images taken through a Baader IR-pass
filter (685 Nm +) and a Hoya IR pass filter
(830 Nm +). The biggest limit to what can
be resolved is the steadiness of our own
atmosphere. In theory resolution increases
as the wavelength of observed light is
reduced, which should make blue or even
ultraviolet the filters of choice for planetary
observers seeking maximum detail. But
these are the parts of the spectrum most
scattered by the atmosphere. So, IR filters
are a compromise; they can’t provide the
ultimate detail visible at shorter
wavelengths on a steady night, but with
poor seeing they can provide the maximum
amount of detail that conditions allow. In
Mike’s case, a combined image using red
light and two frequencies of IR allows
almost all the Cassini Division to be
resolved along with a hint of the Encke
Gap and all major banding in the planet’s
cloud structure. An excellent example of
how to make the most of conditions.
Dave Finnigan, now imaging with a 12-
inch SCT and a DBK21 colour camera, also
made some comparisons. To get the best
from his captured video files he ran them
through both v5 and v6 of Registax and
through v2 of AutoStakert. These are all
excellent bits of freeware and Dave wanted
to see which produced the best result from
a single AVI video of Saturn taken in poor
seeing. In each case the software selected
the best 1,000 frames from the file, then
combined and stacked them into a single
image. The results were close; all three
images showed some evidence of
misaligned frames but the best
combination, by a slight margin, came from
AS2 while R6 just beat R5. Choosing the
number of images to extract and stack
from a video file is a tricky. Some think
that more is always better, while others
(like myself) think that only the best 10%
or so should go into the stack to produce a
final image. More often produces a
smoother, more natural-looking result;
fewer can give a more detailed if somewhat
grainy image. The best advice is to stack
more images if seeing is good, fewer if it is
bad, and play around with the number to
see which gives the most pleasing result. I
agree with Dave that AS2 is currently the
easiest stacking-software to use.
More comparisons of equipment and
technique came from Martin Lewis, who
normally images planets using a DMK21
monochrome camera and colour filters. He
recently began using a one-shot-colour
camera to see if good results can be
obtained with less time spent on image
processing. At the moment the very best
amateur planetary images are rather
painstaking to produce. First, a
monochrome camera is used to take videos
through red, green and blue filters. A
number of these are taken alternatively
over an extended period and each file is
individually processed to produce an
image. These multiple images are then fed
into WinJUPOS, freeware which maps
each image onto a spheroid the same shape
as the target planet, precisely layering and
positioning each image according to the
exact time it was taken. This allows the
extraction of a final colour image that
avoids blurring caused by the planet’s
rotation during the extended capture.
Martin tried layering an image of Saturn
taken with one camera, a monochrome
DMK21, over a colour image taken with an
ASI-120MC, as a luminance layer. This
required taking just two images, which can
be done quickly enough to avoid blurring
due to planetary rotation. The result is
sometimes comparable to WinJUPOS
images and Martin reports that the time
savings are huge. He also uses an
Atmospheric Dispersion Corrector (ADC,
referred to in previous reports) when
observing low targets. He compared two
colour video runs, one with and one
without the ADC. The results are shown
on p47; the device clearly gets the best
from low altitude targets, especially since it
can be used visually as well as
photographically.
Finally, Marc Delcroix
(non-member) imaged
Uranus on 1 July
through a big telescope
from the French
Pyrenees (shown here)
using a monochrome camera and Baader
infrared pass filter (685 Nm +). Subtle
banding on the planet was captured. I
leave this as a challenge for a member to
better in the next reporting period?
Alan Clitherow
Saturn, the only game in town
Section reports
Saturn, from SPA report form for
2 June, with intensity estimates.
Planets
Observer: Matthew Barrett.
p38 Popular Astronomy www.popastro.com November-December 2013
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The Deep Sky Section has received
observations from three members in
the past couple of months: Dale
Holt, Dave Finnigan and Eddie
Carpenter.
Dale sent in five
observations using his Watec
120N+ astro video camera
combined with either his
20-inch Newtonian or 6-
inch refractor. Starting in
Sagittarius, Dale observed
M21, a small open star
cluster. With his refractor
it showed pretty much the
central region of the
cluster, a lovely circular
ring of stars. Also in
Sagittarius, Dale observed
NGC 6642, a small globular
cluster located near M22. This
object is very distant, and being in
the plane of the Milky Way it is
obscured by lots of interstellar
dust. Dale’s sketch shows a
very compact ball of stars,
very granular in appearance
with a few brighter
superimposed stars.
Moving into Aquila,
which again is in the plane
of the Milky Way, Dale
observed the faint galaxy
NGC 6814. The position of
this galaxy means that it is
obscured by lots of interstellar
dust, and through the eyepiece it
appears quite diffuse. Dale
managed to record some slight internal
detail, a faint central core and a mag.
+13.5 star within the galaxy itself.
An interesting planetary nebula can be
found in Cygnus. NGC 7026 also has the
interesting nickname of the ‘Cheeseburger
Nebula’ as it resembles a burger seen
from the side. Dale mentions that his
refractor actually gave a sharper view of
the nebula and split the two sides more
clearly, showing the central star.
Our next contributor, Dave Finnigan,
sent in eight observations using his 12-
inch LX 200 ACF at f/6.3 and a DSI II pro
camera. His first observation was of the
large bright globular cluster M2, which
was well resolved. Another globular, M14,
pretty much filled the frame; this object
had masses of stars and actually looked
three dimensional.
Moving down to Sagittarius Dave
observed M22. His very nice observation
showed a large globular, the central
region consisting of fainter stars with
several brighter stars scattered across its
face. Dave also observed globular cluster
NGC 6712, located in Scutum. This is a
very dense cluster and looks like a solid
ball of stars. One final cluster observation
was of M71, a moderately loose cluster
with a good range of stellar magnitudes.
Dave also sent in colour
images showing M27 and
M57. M27, the famous
Dumbbell Nebula, has a
beautiful blue/green and
pink/red colour and the
central star is well seen.
M57, the equally famous
Ring Nebula, is very well
exposed and again has good
colour; its central star and a
fainter one within the ring
itself is seen. The image is
shown in colour on p47. One
final observation from Dave is
of the recent Nova Delphini;
although no details of a magnitude
were given the image is of a high
magnification and shows it very well.
Our final report is from Eddie
Carpenter. Using 10×50 binoculars he
observed Nova Delphini, which was
visible as a faint star in a 6° field,
although no magnitude estimate is given.
One final note. Due to work and other
commitments I have decided to stand
down from the section, so this will be my
final report. Please hang on to your deep-
sky observations until a new director has
been appointed. If anyone would like to
take on the role, please contact myself or
Guy Fennimore; contact details on p46.
Darren Bushnall
Left: Dale Holt’s observational drawing
of the small, compact globular cluster
NGC 6642 in Sagittarius.
Cheeseburger on chips
Deep-sky
Section reports
Below: Dave
Finnigan
took this
splendid
image of
M27, the
Dumbbell
Nebula, a
large planetary
nebula in
Vulpecula.
The ‘Cheeseburger Nebula’
(NGC 7026), observed
by Dale Holt.
November-December 2013 www.popastro.com Popular Astronomy p39
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Comets I hope you will get up early in the
morning of 1 December to see the tail of a
Great Comet stretching across the sky.
That is what the hype on the Internet
surrounding comet 2012 S1 (ISON)
suggests that you will see, but does the
evidence bear this out?
Magnitude observations to date follow
the comet from 5.4 to 2.0 au on its way to
perihelion at 0.01 au. This sounds as if it
may be more than half way there, but
when we look at comet magnitudes we
need to take the logarithm of the distance,
and on this scale it has only moved from
0.73 to 0.30, and has to get to -1.91, so
there is a long way to go yet. The
consequence of this is that small errors in
magnitude estimates, combined with
differences between observers and
observing techniques combine to give
quite a large uncertainty in the peak
magnitude at perihelion. Whilst the
indications are that the comet may get as
bright as Venus, it could get brighter, or it
could be as faint as 4th magnitude.
Beware any Internet predictions that you
see that don’t mention error bars!
If the comet behaves according to the
most likely estimate we will have a comet
with a pretty long tail that will be worth
getting up for. On the other hand, the
worst case will be that it dies on the way
in to perihelion and there will be nothing
to see by early December.
We could still be in for surprises. The
comet passes within the solar Roche limit,
the distance at which a body held
together by its own gravitational pull
disintegrates. If the comet is fragile it
might therefore fragment and expose a
large area of fresh material that would
lead to a huge outburst in brightness.
Some people have called 2012 S1
(ISON) a Sun-grazing comet. Many of the
real Sun-grazing comets of the Kreutz
Group actually kiss the surface of the Sun
at 0.0046 au, whereas comet ISON only
gets to 0.012 au, which is close but
nowhere near the surface. It is better to
call it a Sun-skirting comet, though this
name is also associated with comets of the
Machholz Complex.
An explanation of these two
names is in order. The Kreutz
Group of comets was first
recognised by Heinrich Kreutz
at the end of the 19th Century
when he suggested that some of
the spectacular comets with
small perihelion distances, and
retrograde orbits with an
inclination of around 144°, were
related. Comet ISON is not a
member of this group. The
Machholz Complex is named
after comet 96P/Machholz and
studies of its orbital evolution
show that this comet is linked to
the Marsden and Kracht comet
groups seen by the SOHO
spacecraft, the daytime Arietid
meteors of June, the southern
Delta Aquarid and the
Quadrantid meteors, asteroid
2003 EH1 and possibly comet
1490 Y1.
There are also suggestions
that a meteor shower might be caused by
comet ISON. This is very unlikely. For a
spectacular meteor shower to occur the
Earth would have to pass close to the
debris trail laid down by the comet, and
which we initially see as its tail. The
Earth does pass 0.02 au from the orbit of
comet ISON in 2014 January, but
unfortunately it is nowhere near the
comet or its dust trail at the time.
Even if comet ISON doesn’t perform,
there are a few other comets around.
2P/Encke comes around every 3.3 years,
and this year the return favours the
Northern Hemisphere. The comet often
has a large and diffuse coma, and
although it may get to easy binocular
brightness, you will need dark skies to
spot it. Ideally use large binoculars rather
than a telescope, as the lower
magnification often does better.
Another periodic comet returns, though
154P/Brewington will be a telescopic
object of around 10th magnitude. Possibly
the most likely to be seen is another
discovery by Terry Lovejoy, designated
2013 R1 (Lovejoy), which could become
a binocular object, moving rapidly below
the Plough when brightest in November.
Keep an eye on the section web page at
www.ast.cam.ac.uk/~jds for updates.
Hopefully 2012 S1 (ISON) will put on a
spectacular show and we’ll get some
superb images to grace the cover of
Popular Astronomy.
Jonathan Shanklin
Editor’s note: Thanks to the vigilance of
Oliver Greenwood, a mistake was spotted
in my graphic of the tracks of comets
Encke and ISON in the Sep-Oct issue of
Popular Astronomy at the bottom of p45.
The comet labels are the wrong way
round; the top track is actually that of
Encke’s Comet, while the lower track is
ISON’s. The graphic at the top of p45 is
correct. Sorry for the confusion! PG
Will C/2012 S1
(ISON) be the comet
of the century?
Section reports
Comet ISON imaged on 8 October
with the 32-inch Schulman
Telescope at Mount Lemmon,
Arizona. Credit: Adam Block /
Mount Lemmon SkyCenter /
University of Arizona.
Left: ISON wasn’t quite bright
enough to be seen through 10×50
binoculars at this stage.
p40 Popular Astronomy www.popastro.com November-December 2013
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Reports, news and notesfrom the Society forPopular Astronomy
THE SPA’s year
of special
events to celebrate our
Diamond Jubilee
continued with a
splendid weekend of
events in Belfast.
The society made its
first ever trip across the
water to Northern
Ireland for what was
originally intended to be a day-long
meeting on 21 September at Queen’s
University.
But our hosts at the university
turned the event into a wonderful
weekend for members who travelled
from the mainland by plane or boat to
attend, joined by members of the Irish
Astronomical Association.
An excellent day of talks was
organised by Professor Alan
Fitzsimmons of Queen’s in a brand
new lecture theatre. Presentations
included latest results on
the Sun, techniques to
find protoplanetary
discs, the sky as
seen from Mars,
new ways to spot
exoplanets and
what causes
supernova
explosions.
Highlights came
with the final two
talks. Alan
Fitzsimmons
presented his
predictions for the behaviour of
incoming Comet ISON—a forecast
that rapidly swept the world thanks
to social media—and then our former
president Professor Iwan Williams
spoke on meteors and fireballs with
the latest information about
February’s Chelyabinsk bolide.
A great day ended with a highly
enjoyable meal at a local Italian
restaurant. But there was more to
come. The organisers had laid on a
coach trip to Armagh on Sunday to
visit the historic Armagh Observatory,
where we were welcomed by its
Director Professor Mark Bailey.
We were further honoured with an
invitation to a lunch reception from
the Lord Mayor of Armagh, Robert
Turner. Cllr Turner revealed his
research into the SPA’s history as he
recalled that the first director of the
Armagh Planetarium had been one of
the society’s founders, Sir Patrick
Moore. Our president Professor Derek
Ward-Thompson thanked the Lord
Mayor for his warm welcome.
The society would like to
acknowledge the support of the Royal
Astronomical Society in making it
possible to hold these regional
meetings.
Paul Sutherland
The photo below shows the Lord
Mayor welcoming members to Armagh
Palace. Picture credit: John Merry.
Wonderful
weekend in
Belfast
The Society Pages
November-December 2013 www.popastro.com Popular Astronomy p41
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The Society PagesCome to the SPA meeting
on 25 January 2014
Citizen Science:
a Revolution in
Your BrowserA talk by
Dr Robert Simpson(Oxford University)
Dr Simpson is an astrophysicist
whose research involves
understanding how stars form.
He works at the Zooniverse, a
world-leading Citizen Science
platform. In this talk Dr Simpson
describes how
Zooniverse has the
potential to enable
everyone with access
to the Web to
perform
‘real’
science.
Astronomer Royal addresses
successful SPA Convention
THE SPA Convention
held on Saturday 12
October proved to be a
great success. Over 250
people enjoyed a day of
talks, exhibits by Section
Directors, trade stands,
plus solar observing and
telescope tours, thanks
to the usual impeccable
organisation by Guy
Fennimore and Barry
Turvey.
The highlight of the
day was the Sir Patrick
Moore Lecture, given this year by the
Astronomer Royal himself, Prof. the
Lord Rees. If you couldn’t make it
along, or simply want to watch the
talks by Lord Rees, Mark Hurn and
Nik Szymanek again, you can do so
online via our Meeting Videos page
at www.popastro.com.
Lord Rees ponders the
question: will the next
60 years see as many
advances as the
last 60? Image
from video by
John
Chapman-
Smith.
Explore the
Universe in
Cardiff
TALKS by top cosmologists and
astrophysicists are a feature of
the SPA’s special Cardiff meeting
on 7 December 2013.
The meeting, to be held at Cardiff
University, is the last in a series
held around the country to
celebrate the society’s 60th year.
Speakers and subjects include:
Prof Matt Griffin, The European
Space Programme.
Dr Enzo Pascale, Balloon-borne
Astronomy.
George Ford, Multi-wavelength
astronomy.
Profs Steve Eales & Jon Davies,
The Dark Matter Debate.
Though admission to the meeting is
free to both SPA members and non-
members, we require attendees to
register with us in advance. Please
email your name, address and SPA
membership number (if any) to
The trade/display section.
The SPA 60th anniversary cake,
created by Barry Turvey.
Guy Fennimore at the well-stocked
SPA merchandise stand. All
images by John Chapman-Smith.
p42 Popular Astronomy www.popastro.com November-December 2013
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Sat 7 December 2013. SPA 60th anniversary event.
Welsh Regional Meeting, Cardiff University. See page
opposite for more details.
Sat 25 January 2014. 2 pm, Khalili Lecture Theatre,
School of Oriental & African Studies. Our main speaker
will be Dr Robert Simpson (Oxford) on The
Zooniverse—turning everyone into a scientist. Following
the break, Robin Scagell will describe what’s coming in
the night sky, and James Hilder will show us how much
of the southern hemisphere skies you can view from the
UK—including some amazing observations made from a
rooftop just yards away from our meeting place! For the
latest society news and info, see www.popaastro.com
Please note:
meetings start at
2pm and end at
5pm
SPA meetings to come
SPA statement on threat to The Sky at Night
FOLLOWING reports that the BBC
may be considering closing down
The Sky at Night TV programme, a
petition has been started to try to save
the programme. The SPA has also
issued an official statement giving its
views.
It has emerged that the BBC will be
‘discussing the future of the
programme’, which has been running
since 1957. It is scheduled to run until
December, after which its future is
uncertain. While the discussions could
be no more than a regular review,
which one would expect to happen with
every programme from time to time,
some people regard this as BBC jargon
for closing the show.
A group of students at the Open
University, led by SPA member Karen
Barker, have started a petition about
the programme, which at the time of
writing has over 35,000 signatures.
While acknowledging that a review
does not necessarily mean that the
programme will be cut, it specifically
requests that the style of the
programme not be changed. The
petition states:
‘We want to see The Sky at Night
continue in much the same way as it
always has: pitched in a scientific
manner towards people who are
knowledgeable on the subject, whilst
retaining its accessibility for newcomers
to the hobby with items aimed at them.
We believe that it should be presented
by professional scientists and/or highly
regarded amateurs, bringing the latest
news and information on the subject to
the people who want it. We do not want
to see it fronted by a generic television
presenter, or a ‘celebrity’ with no
connection to the hobby. It is a
specialist, scientific programme and
should be treated as such and with
respect to its origins and longevity.’
The story has been covered in the
national press, such as a very
sympathetic piece in The Scotsman by
Fiona McCade. who concludes, ‘The
BBC would be mad to let The Sky at
Night go, which means that it probably
will.’
Anyone who wishes to add their name
to the petition can do so at
www.change.org/en-GB/petitions/the-
bbc-please-do-not-axe-the-sky-at-night.
Please note that this will result in your
receiving emails about other campaigns
though you can then unsubscribe from
these. There is a Facebook group for the
petition but note that you need to be
registered with Facebook to view this.
On 1 October the SPA issued the
following statement:
‘The Sky at Night television
programme has been a source of
inspiration to all who have watched it
since its inception in 1957. It has
encouraged an interest in scientific
topics beyond just astronomy, from
people in all walks of life. Many of
today’s scientists gladly state that they
owe the awakening of their interest in
science to this programme.
The Society for Popular Astronomy
strongly exhorts the BBC to continue
this programme beyond the current
planned schedule of December 2013.
The ratings for this programme have
continued to be high, even after Sir
Patrick Moore sadly passed away last
year. The popularity for this
programme and this subject remains
undimmed. The BBC has a treasure in
this programme, which it would be
reckless to squander.
Furthermore, the SPA also strongly
urges the BBC to maintain the current
format of the programme. The
astronomical community is unanimous
in its belief that the style of this
programme is what has made it last for
so long. Its current presenters have
continued to cover a wide range of
astronomical topics in a style which is
accessible to a general audience while
not compromising the underlying
science or trying to over-simplify it.
The success of many other specialist
programmes, such as Springwatch or
Gardeners’ World, is due to the same
general approach—using presenters
who know their subject and are able to
take the audience with them into the
heart of the subject. We trust that the
BBC will see fit to continue The Sky at
Night in its current format.’
Robin Scagell
SPA Vice-President
The Society Pages
SPA meetings are usually held on the last
Saturday of January, April, July and October
in the Khalili Lecture Theatre of the School of
Oriental and African Studies, University of
London, Thornhaugh Street, Russell Square,
London, WC1H 0XG. Meetings start at 2pm and
last until 5pm, including a break for
refreshments. Members and their friends are
welcome, entry is free and there’s always a
friendly atmosphere. Members should remember
to bring their membership card or a copy of PA.
Directions to the venue: When you leave Russell
Square station, turn left and cross the road
straight away. SOAS is on the far corner of
Russell Square. Use the entrance marked,
opposite the Brunei Gallery. When you enter the
SOAS building, sign in as a visitor to the
university at the reception desk, where you will
be given a visitor sticker which you should keep
visible, and go through the entry gate. The
Khalili Lecture Theatre is downstairs—look for
the SPA signs. We also have our own signing-in
book before you enter the lecture theatre.
November-December 2013 www.popastro.com Popular Astronomy p43
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Sky Diary
Moon phases
Meteor notesNovember. The Taurids produce
observed rates of a few meteors per
hour in the first half of November.
Moonlight will hinder evening sky
observations after the first week.
The Leonids peak on 17 November,
but observing circumstances are very
unfavourable this year with full Moon
also occurring on the 17th.
December. The Geminids, the most
active meteor shower of the year, are
active from around 5 to 16 December,
with peak rates (ZHR over 100)
predicted for the night of 13-14
December. Unfortunately observations
of this year’s Geminid maximum will
be seriously hindered by a bright
gibbous Moon in Aries which will be
high in the evening sky and will not
set until around 05h.
The Ursids start close to the date of
full Moon, but slowly become more
favourable and will produce peak
observed rates of a few meteors per
hour around 21-23 December.
Additional information about meteor
activity during this period can be
found at
www.popastro.com/meteor/reference
/meteorshowers/ index.php.
Tony Markham
Apsides
OccultationsReappearance
Disappearance
Dark limb
Bright limb
The position angle (PA) of theoccultations given below is
measured anticlockwise from thenorthpoint of the Moon’s disc (usethe Moon’s north pole as a guide).
Date Object Mag Phase Data for Greenwich Data for Edinburgh
Time Alt° Az° PA° Time Alt° Az° PA°
10 Nov 46 Capricorni 5.1 DD 19h 16m 29 194 84 19h 11m 25 189 73
19 Nov NGC 1647 star 6.0 RD 01h 58m 55 207 247 01h 54m 52 198 261
19 Nov 97 Tauri 5.1 RD 05h 03m 33 259 276 04h 53m 35 251 285
22 Nov Lambda Geminorum 3.6 DB 00h 22m 41 120 147 00h 16m 37 118 129
22 Nov Lambda Geminorum 3.6 RD 01h 15m 48 135 230 01h 22m 44 136 248
24 Nov 60 Cancri 5.4 RD 01h 59m 38 125 346 Appulse
11 Dec Epsilon Piscium 4.3 DD 22h 16m 36 230 95 22h 07m 35 222 79
14 Dec Sigma Arietis 5.5 DD 02h 39m 18 272 84 02h 32m 21 266 74
21 Dec 50 Cancri 5.9 RD 06h 00m 35 243 326 05h 47m 36 233 331
22 Dec Omega Leonis 5.5 RD 02h 32m 46 161 262 02h 30m 41 157 272Note: These are the only occultations for this period, based on the criteria below. More information, see Occultation Section report.
Mag: Visual magnitude. Phase: (R)eappearance, (D)isappearance or (G)raze at (D)ark or (B)right limb of the Moon. Alt: Altitude. The Moon’s height at the time of the
occultation. Az: The angular position along the horizon measured clockwise from true north (through E, S, W back to N). PA: Position Angle of the event, measured
anticlockwise from the direction of the Celestial North Pole. This listing shows lunar occultations of stars brighter than mag +6, observable with small telescopes in a sky dark
enough to be seen without difficulty. Specific data for your own locality or for details of fainter occultations, contact Occultation Section Director Mell Jeffery (address on p46).
Date Apsis Dist (km) Size
6 Nov, 9h Perigee 365,361 32’ 42”
22 Nov, 10h Apogee 405,445 29’ 29”
Date Apsis Dist (km) Size
4 Dec, 10h Perigee 360,063 33’ 11”
20 Dec, 0h Apogee 406,267 29’ 25”
New First quarter Full Last quarter
3 Nov, 12:50 10 Nov, 05:57 17 Nov, 15:16 25 Nov, 19:28
3 Dec, 00:22 9 Dec, 15:12 17 Dec, 9:28 25 Dec, 13:48
270°
180°
0°
90°
A summary of sky eventsfrom November to
December 2013 (UT times)
Comets ISON and Encke, November
This chart shows the path of both comet 2P/Encke and C/2012 S1 (ISON)
throughout November at daily intervals. Also marked is the daily path of the
Sun and the positions of Mars, Mercury and Saturn on 15 November. PG.
1 Nov
1 Nov
30 Nov
30 Nov30 Nov
p44 Popular Astronomy www.popastro.com November-December 2013
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Solar SystemMercury makes its best appearance of
2013 during November. Following
inferior conjunction on 1 November, the
planet quickly heads west of the Sun
and emerges into the morning skies.
Mercury can be spotted quite easily
with the unaided eye throughout the
latter part of November, given a
clear, flat east/southeastern horizon.
Greatest elongation west takes place
on 18 November, when it is 20° from
the Sun; it rises at around 04:40, almost
two hours before sunrise, has climbed to
5° by the end of astronomical twilight and
is 15° high at sunrise. At mag. -0.5, Mercury
is 6.7 arcsec. across and 60% illuminated at this
maximum elongation.
Comet Encke (mag. +4.6) lies just over 1° southwest of
Mercury on the morning of 18 November, both visible in the
same low-power telescopic field for a few days around this
time. Another close Mercurian encounter takes place on 26
November, when it passes within ½° south of Saturn (mag.
+0.6). This will be a delightful scene through a telescope with
an eyepiece that holds both planets in the same field.
As it draws closer to the Sun the planet is effectively lost to
view from the end of the first week of December. Superior
conjunction takes place on 29 December.
Venus has been loitering in the skies east of the Sun since
the spring, but its low elevation at sunset hasn’t allowed it to
show off. Venus’ greatest elongation east takes place on 1
November, 47° from the Sun and shining at mag. -4.4.
Measuring 25 arcsec. in apparent diameter, Venus’ dichotomy
(half-phase) occurs around this time. Heading back towards
the Sun, its apparent size increases as it becomes ever more
crescent-shaped. By the end of November it is 37 arcsec.
across, 31% illuminated and shines a brilliant mag. -4.6. By
the year’s end Venus is mag. -4.4, some 10° high at sunset,
and telescopically appears a large (59 arcsecond) but narrow
(4% illuminated) crescent.
Mars treks from mid-Leo into western Virgo
during November and December, a
continually improving morning object
steadily increasing in brightness and
apparent size. Mars has grown larger
than 5 arcsec., large enough to be
considered worthy of serious telescopic
study and CCD imaging. At the end
of November Mars is 72° west of the
Sun, rising at 01h, and is 38° above
the south-eastern horizon by the end
of astronomical night.
On 17 November at around 03h Mars
passes close to Sigma Leonis (mag.
+4.0), the pair being separated by just 35
arcseconds—tough to split in binoculars.
By the end of December the Red Planet
shines at mag. +0.9; rising at around 00:30 it
transits the meridian at an altitude of 37° nearly two
hours before sunrise. Now 6.8 arcsec. across, observable for
3½ hours against an astronomically dark sky at more than
20° high, it’s time to refamiliarise ourselves with Mars, its
fascinating features and nomenclature.
Jupiter continues its rise in the late evening/early morning
skies. Located in mid-Gemini, the planet brightens from mag.
-2.4 to -2.7 and its apparent diameter increases from to 41 to
47 arcsec.during the course of November and December. At
the beginning of December Jupiter rises at 19h and transits
the meridian at 03h, some 60° high. Things have improved
yet further by the year’s end, when it rises at 17h and
transits at 01h; by 06h, near the end of astronomical night it
is 20° high. This means that Jupiter can be followed at a good
altitude in a dark sky for more than 10 hours, enabling an
entire rotation of the planet to be observed in a single night.
Saturn undergoes conjunction on 6 November. It begins to
emerge in the morning skies within a few weeks.
Uranus (mag. +5.7, 3.4 arcsec. across) and Neptune (mag.
+7.8, 2.4 arcsec. across) are both evening objects in Pisces and
Aquarius respectively.
The path of Comet
Brewington through
Pegasus plotted at
daily intervals
between 1 November
and 31 December.
The comet will be a
9-10th magnitude
binocular object at
its best in late
November.
Sky Diary
December—ISON
heads north
Comet 154P/
Brewington
The northward path of
Comet ISON during
December, plotted at
daily intervals between
1 and 31 December.1 Dec
31 Dec
26 November—
Mercury and
Saturn.
November-December 2013 www.popastro.com Popular Astronomy p45
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Observing Section DirectorsOfficersSecretary
Guy Fennimore
36 Fairway
Keyworth
Nottingham
NG12 5DU
Membership Secretary—
enrolments, renewals and
changes of address
Barry Turvey
36 Fairway
Keyworth
Nottingham
NG12 5DU
Treasurer
Helen Walker
38 Edwin Road
Didcot
OX11 8LE
Webmaster
Popular Astronomy Editor
Peter Grego
7 Parc-An-Bre Drive
St Dennis
St Austell
PL26 8AS
Publicity Officer
Mandy Bailey
22 Christine Avenue
Wellington
Telford
TF1 2DX
SPA Council Members
Paul Millington
Ian Morison
Margaret Penston
John Chapman-Smith
Paul Sutherland
Weekend Course Organiser
Guy Fennimore
36 Fairway
Keyworth
Nottingham
NG12 5DU
SPA Advisory Services
Patron: Professor Sir Arnold Wolfendale, FRS, 14th Astronomer Royal
Society for Popular Astronomywww.popastro.com
President: Prof Derek Ward-ThompsonJeremiah Horrocks Institute, University of Central Lancashire, Preston, PR1 2HE [email protected]
Vice Presidents: Prof Ian Robson [email protected] / Robin Scagell [email protected]
Aurora Sandra Brantingham, Trevona, Glenbarry, Banff, AB45 2HJ
[email protected] Website: www.branters.freeserve.co.uk/
Comet Jonathan Shanklin, 11 City Road, Cambridge, CB1 1DP
[email protected] Website: www.ast.cam.ac.uk/~jds/
Deep Sky Darren Bushnall, 270 Owton Manor Lane, Hartlepool, TS25 3RL
[email protected] Website: homepage.ntlworld.com/darren.bushnall/
Lunar Peter Grego, 7 Parc-An-Bre Drive, St Dennis, St Austell, PL26 8AS
[email protected] Website: www.lunarobservers.com
Meteor Tony Markham, 20 Hillside Drive, Leek, ST13 8JQ
Occultation Mell Jeffery, 11 Chestnut Grove, Norton, Malton, YO17 9BZ
Planetary Alan Clitherow, Coldene, Bridgend, Ceres, Cupar, KY15 5LS
Solar Geoff Elston, 59 Nalders Road, Chesham, HP5 3DQ
Variable Star David Scanlan, 87 Withy Close, Romsey, SO51 7SA
Young Chief Stargazers, George Ford and Ezzy Pearson
Stargazers [email protected]
The SPA section directors are happy to help members with all aspects of
observing. Many sections have their own printed leaflets and observing
forms which can be obtained by post or via the SPA website at
www.popastro.com.
Please send your astronomical observations (notes, observational drawings
or images) to the section directors by post or by email attachment. The SPA
advisors are happy to answer questions about their own astronomical
specialties. If using regular mail, please enclose a suitably sized stamped,
self-addressed envelope when corresponding with directors and advisors.
Astronomy Tony Sizer, 88 Cumberland Avenue, Welling, DA16 2PU
GCSE [email protected]
Astro Imaging Nik Szymanek, 186 Thorndon Avenue, West Horndon, Brentwood, CM13 3TP
[email protected] Website: www.ccdland.net
Cloud Watch Terry Holmes, 34 Sycamore Road, Tipton, DY4 9RN
Instrument Ian Morison, 4 Arley Close, Macclesfield, SK11 8QP
Light Pollution Martin Morgan-Taylor, 39 Sports Road, Glenfield, Leicester, LE3 8AL
Liaison Officer [email protected]
p46 Popular Astronomy www.popastro.com November-December 2013
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Celestial rings
RING structures abound in the
Universe, and here are some
lovely, easily observed examples.
At top is Mike Brown’s image of
one of the most spectacular areas on
the Moon—the region bounding the
northwestern shore of Mare
Nectaris, with craters Theophilus,
Cyrillus and Catharina. Victorian
astronomers liked to call such large
craters ‘ring mountains’.
At centre is the unmistakable
ringed planet Saturn, imaged by
Martin Lewis (see Planetary Section
report on p38 for details).
To the right is the famous Ring
Nebula (M57) in Lyra, imaged by
Dave Finnigan (see Deep Sky Section
report on p39 for details). Dave Finnigan
Martin Lewis
Mike Brown
November-December 2013 www.popastro.com Popular Astronomy p47
PA_2013-1112 Adlard:PA_2013-1112.qxd 29/10/2013 16:07 Page 44
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