The Southern Astronomer No.99 – December 2016
SOUTHERN ASTRONOMER THE
MONTHLY MAGAZINE OF WORTHING ASTRONOMERS & WORTHING SKYWATCHERS
© Amit Kamble
The Southern Astronomer No.99 – December 2016
WORTHING ASTRONOMERS No fees, no Committee; just enjoying the night sky together.
F
ormed in 2008 by a group of regular and practical observers, Worthing Astronomers is a free to join society now with a membership of over 450 persons, who have a common interest in Astronomy and its associated subjects – no internal politics, no fees, no committees, just astronomy!
The Southern Astronomer This Issue Astronomy This Month Observing : The Planets The Saros Cycle The Moon & The Sun Meteors & Comets December Workshop Preview Looking Up: December Night Sky & Monthly Sky Map
Our aim is simple – to bring astronomy to the public in general and to help and assist our membership in observing the night sky. With the aid of this newsletter, website, social media, regular star parties, workshops and public observing events we hope to encourage and share our interests in observing the sky with the public, our colleagues in our own group and with those of neighbouring astronomical societies.
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p.3 p.4 p.5 p.6 p.7 p.8
Cover Picture & Comment
We try and meet at least once a month (when weather conditions allow) to do some observing but we do hold every two months a Workshop evening when we get a chance to meet up, exchange ideas and tips and help each other to make the most of observing the sky above us. Occasionally a guest speaker will talk about an aspect of practical, hands on astronomical observing.
Another year has rolled around and it only seems a short while ago I was dragging the artificial Christmas tree up into the loft, only having to get it down again! The picture I have chosen to be the front cover this month is a view of pine tree with a crescent Moon with earthshine, Venus and lower left, even a comet.
These Workshop evenings are held on the first Friday of every other month (February, April, June, August, October and, December) at Goring Methodist Church Hall, Bury Drive (off of Aldsworth Avenue), Worthing, BN12 4XB. The admission charge of £3 helps pay for the room and free refreshments and goes towards supporting our membership. Doors open at 7.00 pm with the meeting starting at 7.30.
A beautiful picture just right for the season by Amit Kamble in New Zealand. We have the last Workshop of the year coming up which will be our Christmas and New year social – it will be free entrance for WA and Sky Watchers – details on page 7.
We can be found at: worthingastronomers.org.uk
The coming year has lots of astronomical things going on and a preview of some these will be given at the December Workshop plus, we have been approached by some local bodies who are interested in getting together with us and link up to do some observing with them – details, as and when on Facebook, website forum and of course, this newsletter!
There are several astronomical groups in the coastal area of Sussex - several WA members are also members of the Adur Astronomical Society, who meet every first Monday of the month for a lecture regarding an astronomical subject. Details for the AAS can be found at Adur Astronomical Society.
It is now just up to us to wish you all the greetings of the season no matter what your persuasion or beliefs and let us hope for clearer skies in 2017.
Jan and Brian
CONTRIBUTIONS AND UNSUBSCRIBING Contributions – written articles (word processed in .txt, .doc or .odt format), photographs, letters, advertising copy to the editor for the January issue should be in by December 15 and sent to the editor at the contact address: editor@worthingastronomers.org.uk
Contact addresses: Joint coordinators - info@worthingastronomers.org.uk – general society details, Janet Halls or Brian Halls
If you no longer wish to subscribe to the group and cancel newsletters and other information, please send an email to: info@worthingastronomers.org.uk with 'Unsubscribe' in the subject line; we do not want our stuff to end up like spam littering your inbox.
treasurer@worthingastronomers.org.uk – donations contact Janet Halls outreach@worthingastronomers.org.uk – events contact Steve Bassett, Mike Williams
Volunteers are always welcome: if you want to find out more, call 01903 521205 or drop us a line at the e-mail address above.
website@worthingastronomers.org.uk – contact for website Perry Wilkins
If you like the newsletter or its content please feel free to distribute it to anyone you know who might be interested. Content is subject to copyright to the group and/or the individuals whose images or articles are used.
editor@worthingastronomers.org.uk – newsletter content detail Brian Halls
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The Southern Astronomer No.99 – December 2016 DEEP SKY OBJECTS (cont)
ASTRONOMY
SUBJECT
Constellation
MAG
RA (h m)
DEC (° ' )
NGC1052 Galaxy
Cetus
10.5
02 41.1
-08 15
December 2016
NGC1055 Galaxy
Cetus
10.6
02 41.8
+00 27
NGC1087 Galaxy
Cetus
10.9
02 46.4
-00 30
All times are expressed as Universal Time (UTC – Co-ordinated Universal Time) and can be considered the same as GMT (Winter Time) Information given, unless otherwise stated is for the 15th of the month at 21.30h. Lunar and other phenomena in the Quick View Diary are shown to the nearest hour.
NGC1084 Galaxy
Eridanus
10.7
02 46.0
-07 35
NGC1199 Galaxy
Eridanus
11.4
03 03.6
-15 37
NGC1209 Galaxy
Eridanus
11.4
03 06.0
-15 37
Officially winter begins on the Solstice (21st) though weather forecasters use the first of the month.
NGC1300 Galaxy
Eridanus
10.4
03 19.7
-19 25
NGC1309 Galaxy
Eridanus
11.5
03 22.1
-15 24
NGC1337 Galaxy
Eridanus
11.9
03 28.1
-08 23
NGC1353 Galaxy
Eridanus
11.4
03 32.1
-20 49
NGC1357 Galaxy
Eridanus
11.5
03 33.3
-13 40
NGC1400 Galaxy
Eridanus
11
03 39.5
-18 41
NGC1407 Galaxy
Eridanus
9.7
03 40.2
-18 35
NGC1421 Galaxy
Eridanus
11.4
03 42.5
-13 29
NGC1440 Galaxy
Eridanus
11.5
03 45.0
-18 16
NGC1452 Galaxy
Eridanus
11.8
03 45.4
-18 38
NGC1453 Galaxy
Eridanus
11.5
03 46.5
-03 58
NGC1461 Galaxy
THIS MONTH
The hours of darkness are at their longest (16 hours) this month. On the 16th there is exactly eight hours between sunrise and sunset (from our latitude). Earliest sunset occurs at 15.59 on the 16th and for the following four days the Sun sets at that time; after that, the Sun sets a little later from now on, yet oddly the Sun still rises later in the morning, rising at 08.05 from December 26 until the end of the year. Cold clear nights will give good seeing if the jet stream shifts allowing cold air from the north to sweep across the country. Frost may even occur and it is not unknown to scrape it off of ones telescope tube during an observing session! Yet, if you are well wrapped against the cold, observing under these conditions can be a pleasure.
QUICK VIEW DIARY 1 7 10 12 14 21 22 25 28 29 31
Sunrise 07.43h : Sunset 16.02h Moon: First Quarter (09h) Moon Rise (13h) Saturn at conjunction (11h) Mercury, greatest elongation east (21°) (21h) Moon at perigee (23h) Full Moon (0h) Trad. English – Oak Moon/Lenten Moon Moon Rise (17h) Moon Rise (0h) Moon: Last Quarter (02h) Solstice (10h) Jupiter 2.3S of Moon (18h) Moon at apogee (06h) Mercury inferior conjunction (18h) Moon Rise (05h) New Moon (06h) Sunrise 08.05h : Sunset 16.08h
Moon phase graphic on page 8
DEEP SKY OBJECTS SUBJECT
TYPE
Constellation
MAG
RA (h m)
DEC (° ' )
NGC891
Galaxy
Andromeda
9.9
02 22.6
+42 21
IC342
Galaxy
Camelopardalis 12
03 46.8
+68 06
Berk65
Open Cluster
IC1848
Clust & Neb Cassiopeia
Cassiopeia
10.2
02 39.0
+60 25
6.5
02 51.4
+60 25
Open Cluster
Cassiopeia
6.6
02 32.6
+61 27
NGC1027 Open Cluster
Cassiopeia
6.7
02 42.6
+61 36
Mel15
Tr3
Open Cluster
Cassiopeia
7
03 11.8
+63 15
NGC1068 Galaxy
Cetus
8.9
02 42.7
-00 01
NGC864
Galaxy
Cetus
10.9
02 15.5
+06 00
NGC908
Galaxy
Cetus
10.2
02 23.1
-21 14
NGC936
Galaxy
Cetus
10.1
02 27.6
-01 09
NGC955
Galaxy
Cetus
12
02 30.6
-01 07
NGC1016 Galaxy
Cetus
11.6
02 38.3
+02 07
NGC1022 Galaxy
Cetus
11.3
02 38.5
-06 41
NGC1042 Galaxy
Cetus
11
02 40.4
-08 26
TYPE
Eridanus
11.8
03 48.5
-16 24
Basel10
Open Cluster
Perseus
9.9
02 18.8
+58 19
Mel20
Open Cluster
Perseus
1.2
03 22.0
+49 00
NGC1039 Open Cluster
Perseus
5.2
02 42.1
+42 47
NGC869
Open Cluster
Perseus
5.3
02 19.1
+57 08
NGC884
Open Cluster
Perseus
6.1
02 22.5
+57 09
NGC957
Open Cluster
Perseus
7.6
02 33.3
+57 34
NGC1023 Galaxy
Perseus
9.4
02 40.4
+39 04
NGC1058 Galaxy
Perseus
11.2
02 43.5
+37 20
NGC1161 Galaxy
Perseus
11
03 01.2
+44 54
NGC1245 Open Cluster
Perseus
8.4
03 14.7
+47 14
NGC1275 Galaxy
Perseus
11.9
03 19.8
+41 31
NGC1342 Open Cluster
Perseus
6.7
03 31.7
+37 22
NGC1444 Open Cluster
Perseus
6.6
03 49.4
+52 40
Tr2
Open Cluster
Perseus
5.9
02 37.3
+55 59
Mel22
Clust & Neb Taurus
1.2
03 47.0
+24 07
NGC777
Galaxy
Triangulum
11.4
02 00.2
+31 26
NGC784
Galaxy
Triangulum
11.7
02 01.3
+28 50
NGC890
Galaxy
Triangulum
11.2
02 22.0
+33 16
NGC925
Galaxy
Triangulum
10.1
02 27.3
+33 35
NGC949
Galaxy
Triangulum
11.8
02 30.8
+37 08
PATRICK’S PITHY PEARLS OF ASTRONOMICAL WISDOM
“Astrology proves one thing only: there’s one born every minute.” ** “Astronomy attracts cranks like a moth to a lamp.” ** “Every nut thinks every other nut is a nut.” **
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The Southern Astronomer No.99 – December 2016
OBSERVING THIS MONTH:
A
PLANETS
s sunset is early, the prominently bright planet Venus at -4.3m can often be taken to look like the Christmas
Star.
We of course have no idea what the star of the Nativity was – even if it really did exist but it certainly was not Venus. From the scale chart below, it is quite obvious how large the planet, looking like a half moon is when viewed through binoculars or even a small telescope. The downside is that the planet is low in the south-west sky but good seeing conditions may give one a chance to look at the cloudy covering of the planet. The best time to look at the planet is when the sky is still bright and the planet is just appearing in the blue sky. Users of GOTO telescopes or those with setting circles may find the planet quite easily before it can be picked up in the sky.
Visibility of the planets and Moon, mid-month
The angular size of the planet is now slowly getting larger - 33.9 arcseconds* - and it is bright in the late sky night or early morning prior to the dawn shining at -1.7m. The cloud belts are always prominent as is the (fading and shrinking) Great Red Spot. There are always of course the four bright Galilean satellites of the planet that even a small telescope can see.
For those not so equipped, Venus lays about 45° east of the Sun at an altitude of 16° at sunset mid-month.
Early in the month, the fleeting planet Mercury reaches its furthest elongation from the Sun on the 10th and will be 21° east of the Sun at sunset. However a good clear For the night-owls among us or, the early western horizon will be required to see it. It risers, Jupiter rises just after 02.00UT. It lays will be 23o west of Venus in line with the Sun. at 5.8 astronomical units from us – the astronomical unit is the average Earth-Sun Mars is also in the evening sky and is visible distance (149 597 870 km). I will let you do at sunset. However, the angular size of the the maths on that one. planet is only 6 arcseconds. Being low in the
south-west, the planet is not at its best, even for those with larger instruments. Ringed planet Saturn is in conjunction with the Sun on December 10, which means the two bodies are close to each other and from our solar system perspective, Saturn is on the far side of the Sun from us. The outer ice-planets, Uranus and Neptune are in the dark evening sky. Neptune lays above and to the east of Mars between the ‘arms’ of Aquarius at 8m while the slightly brighter (5.75m) Uranus is higher up in Pisces, just 39 arcminutes (just a tad over a moon diameter) from the star ζPisces. With the close by star 88 Pisces the three objects make a nice close knit triangle. A good way to find the planet if you have never seen it before. * ASTRO-TALK FOR NEW SKYWATCHERS
Measurement of objects in the sky are measured in degrees, minutes and seconds. The degree (°) is divided up into arcminutes (‘)There are 60 arcminutes in a degree. The arcminute is itself divided up into smaller portions – arcseconds (“). There are 60 arcseconds to 1 arcminute. For clarity the ‘arc’ prefix is often dropped. The Full Moon is about 32’ or ½° in size.
The planets mid-month (comparative angular diameters) – timed at 21.30UT
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The Southern Astronomer No.99 – December 2016
O
THE SAROS EFFECT AND STORY TELLING
utside of science fiction, astronomical events do not appear On Friday February 14, 1794 there was a total lunar eclipse. Mid to normally play a large part in literature or indeed the arts in eclipse occurred 22.21UT (though there was no coordinated general. standard time in the UK during this period.) The whole of the eclipse was visible from the UK and of course, Cornwall. It is reported that I doubt if it has skipped anyone’s notice that one of the most talked the Moon was deep red colour at mid-eclipse. Totality was for 1 about television programmes at the moment is the Mammoth hour 45 minutes. The moon was also close to apogee (furthest from Production of Poldark which has just completed its second series on the earth in its orbit) which 'helped' with the prolonged period of BBC television and is based on the first four books of the Poldark totality. From the graphic, it can be seen that the Moon passed canon. almost centrally through the shadow of the Earth. For those not in the know, it takes place in late eighteenth century Cornwall and the story centres around one Ross Poldark who has returned from the American War and begins to take up life once more as a local squire, farmer and mine owner.
The Poldark eclipse was one of Saros cycle 120. Eclipses of the Moon and Sun occur in cycles which are named Saros, after the Babylonian word saru. The early Mesopotamian’s were aware of this cycle thousands of years ago. The Saros is a period of approximately 223 synodic months (approximately 6585.3211 days, or 18 years, 11 days, 8 hours), that can be used to predict eclipses of the Sun and Moon. One saros period after an eclipse, the Sun, Earth, and Moon return to approximately the same relative geometry, a near straight line, and a nearly identical eclipse will occur, in what is referred to as an eclipse cycle.
He has adventures along the way which I won't burden you with here. The author of the books on which the dramatisation are based was Winston Graham who began writing the series of novels in 1947. You with me so far?
The next Saros cycle 120 lunar eclipse to occur will be in July 2028. The last total solar eclipse of Saros 120 was in March 2015, while the next will be in 2033.
Ross Poldark as portrayed by actor, Aiden Turner. Mrs Editor insists that this picture should be in here...for some reason!
SOLAR ECLIPSES A solar eclipse is mentioned in the Carly Simon song, 'You're So Vain'. There is a line where she sings about an obviously playboy acquaintance that "...flew [your] Learjet up to Nova Scotia to see the total eclipse of the sun."
Book number five in the Poldark novels is called, The Black Moon. This book and the one that follows, The Four Swans are at the moment being filmed for series three due for broadcast in 2017.
Not wishing to give anything away, a serious event in the last series Simon claims to have written the song in 1971. There had been a comes to fruition in The Black Moon with the birth of a child during a total eclipse of the Sun visible from Nova Scotia in 1970. The Valentines Day total lunar eclipse - the Black Moon of the title. eclipse occurred at 17.38UT or early afternoon local time. The Saros series cycle was 139. The next solar eclipse in this cycle is in April 2024. The next lunar eclipse of the cycle is in July 2019 when it will be a partial umbral eclipse - the Moon passes only through part of the darker shadow of the Earth. There was also a total solar eclipse visible from Nova Scotia in July 1972 a year after Simon penned the lyrics to 'You're So Vain.' In his novel King Solomon’s Mines, H Rider Haggard had his hero, Allan Quatermain travelling into what was then deepest Africa in search for the fabled mines of the book’s title. Things get a bit sticky for Quatermain and his client Sir Henry Curtis when they meet up with evil King Twala and they get caught up in inter-tribal war. It is only their fore knowledge of a solar eclipse are they able to bring order when the eclipse begins. Written between January and April 1885. There was a solar eclipse on March 16 that year though this was visible only across Canada and the United States. No year is mentioned though Haggerd may have been influenced by the north Africa eclipse of May 1882.
© NASA/Fred Espanak
I had always thought that Graham had just used a bit of artistic license for this but no, one really did happen on the date and year mentioned in the book. It is said that he was a meticulous researcher.
There are many other other areas where astronomical events play a role in story being told – too many to reproduce here. Perhaps you know of one or two yourself. If so, why not share it with us?
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The Southern Astronomer No.99 – December 2016
OBSERVING THIS MONTH:
THE MOON
Lunar X is visible at first quarter each month – it is just that the Moon may not always be above our local horizon when the lighting is just right.
There are other objects that can be quite challenging as well for the lunar observer – n old friend returns for some of us this the bands of Aristarchus for example or, the lunar domes of the Marius Hills, or the ones month. During the late afternoon of close by the crater Hortensius. December 6, the libration of the Moon, and the angle of the rising Sun across These domes are believed to be a the lunar surface make an area of the geological feature called a shield volcano southern area of the Moon light up like the and are typically formed on the Moon by letter X. highly viscous lava outflows, triggered probably by asteroid impacts. GOOD NEWS FOR X-PHILES
A
Another challenge is to lookout for a feature that appears on the south-western edge of the Moon called the Mare Orientale. We only get to see a small section of this feature from Earth but if it was visible in its entirety it would be one of the most magnificent things to observe on the Moon.
OBSERVING THIS MONTH:
THE SUN
T
he Sun reaches its lowest point in the sky during December. Above the horizon for only about 8 hours it is difficult to glimpse except when we have clear skies. Sunspot activity has been at a low ebb over the last few years and especially the last few months as regular readers of this column will know and this has been the situation during October and November. Brian States made observations of the Sun on 30 days in October. I fared less well with just 8 days. However our average relative sunspot number (R) for the month is 25.21 compared with BAA=27.73; AAVSO=29.4 and SDC=33.6 - a fairly close match! The present sunspot cycle – number 24 since regular solar observing records began – is likely to be the lowest one for about a hundred years, the highest average sunspot number recently was during 2014 when the R was 113. The present cycle is expected to reach a minimum during the early 2020’s. Prior to our present ‘quiet’ sunspot period the last one before that was nearly two hundred years ago and before that, three hundred years ago – are you seeing a pattern here? It may just be a coincidence but, who knows.
© Steve Bassett
The optimum time to see this chance alignment of shadow and light is at 16.36UT but it will be prominent before and after this time for a little while. What are we seeing? We are seeing sunlight striking the walls of three craters, La Caille, Blanchinus and, Purbach. There is also the letter V a little way to the north on the terminator line which is formed by the crater Uckert and smaller features.
© Brian Halls
The Sun has been shining down upon us for the better part of 4 billion years yet we have only been observing it for a mere 400 years.
In the image above the edge of the Mare There is a lot to learn. can be seen as a dark line close to the lunar limb.
*ASTRO-TALK FOR NEW SKYWATCHERS
Libration: We are all pretty used to seeing the face of the Man In The Moon. This is due to the Moon being tidally locked with our planet so it shows the same hemisphere towards us. However at times the northern, eastern, western and southern portions of the Moon can tilt a little towards us revealing tantalising glimpses of pieces of the Moon we cannot see normally. This is due to the Moons own proper motion as it orbits our planet and motions in our own planet as well!
The above image shows the extent of the Mare when imaged from an artificial satellite – Orientale is just left of centre.
Click on the following link: https://en.wikipedia.org/wiki/Libration for a detailed description of the effect and an animated image file that shows a speeded up lunar month and the oscillation which we call libration.
Though only visible when libration* allows, it is a fascinating object to see.
The areas around the lunar edges – limbs – reveal lunar features that do not always appear on standard charts.
© Johnstons Archive
© Rűkl /.wikispaces.com
The impression of an X remains even in the ‘full sun’ image above.
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The Southern Astronomer No.99 – December 2016
METEORS & COMETS
W
hile it might be good for lunar observers the Moon and its light hampers other areas of astronomy – ask any deep sky observer! But it will also interfere with the one of the busiest meteor showers in the calendar. The Geminid meteors reach their peak on December 13 – the day before Full Moon. In recent years the Geminids have overtaken the Perseids as the richest annual shower – a ZHR of 100 or more can be expected - and they produce bright events as well. All this will be hampered by moonlight let alone any adverse weather we may have to encounter. However the start of the Geminids occurs around December 8 and it carries on until the 17th.
Geminid radiant 13th December close by the star Castor
Not affected by moonlight will be the lesser known shower, the Ursids which peaks between the 22nd and the 23rd. The usual limits of the shower are the 17th and December 25. The expected ZHR is about 10. Another but lesser known shower is the December Leonid Minorids – a shower associated with a radiant close to the constellation of Leo Minor. It has a ZHR of 5 and is a spread out event, starting on December 4, peaking on the 19th and ending in early February. Anyone seeing a sporadic meteor not associated with either the Geminids or Ursids it is likely to be one of these. In the evening sky comet 45P/Honda MrkosPajdusakova will be low in the south west after sunset. It will be about 7m and will set soon after the Sun. It will not be far from Venus mid month.
W
45P/Honda-Mrkos-Pajdusakova -centre of cross hairs (December 15)
DECEMBER WORKSHOP EVENING
e meet once again and for the last time in 2016 at our regular meeting place on Friday December 2 – venue details on page 2. As is usual for a December meeting this will be a chance for us to chat over some festive munchies and a cup of tea or coffee (sorry, nothing alcoholic.) However there will be a preview of what is going to happen astronomically speaking in our skies during 2017 and of course a chance to take a look at any photo’s taken
by members since the last meeting – there are some despite the cloud! Another point to remember that this meeting is FREE to members of Worthing Astronomers and Worthing SkyWatchers – if you bring a guest there will be a standard charge on the door for them. This last year has seen its ups and downs – the weather playing a large role in the downs with cloud being in the wrong place at the wrong time despite clarity of the sky prior and after the event we were hoping to observe! The transit of Mercury springs to
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mind in early May, though despite the attempts of the weather to thwart us, some members did get to see it at least. The weather has played no short measure in some of public observing events but, again the weather has been moderately kind to us as well. If you have anything of interest to show at the next Workshop night – pictures etc. or (if the forecast is clear skies) a telescope, feel free to bring it along and you can share it with the members. Let us see what 2017 will bring.
The Southern Astronomer No.99 – December 2016
LOOKING UP: DECEMBER NIGHT SKY As has already been noted on the previous pages of this newsletter, there are many things to see in the night sky over the coming month.
MOON PHASES IN DECEMBER
The Moon, in its own way an absorbing object to observe from night to night, reaches maximum brightness mid month hampering the search for deep sky objects and meteors. During the latter part of December the Moon begins to wane and it rises later and later, making the faint objects in the night sky once more accessible. On page 3 there is the usual list of some of the many deep sky objects (DSO’s) that can be seen during the month. The Cetus and Eridanus area can be quite rich in faint galaxies though a good southern horizon is best for these. For those without that sort of southern aspect there are brighter objects in Perseus which is laying almost overhead and are well displayed for the owner of binoculars or small telescopes, while the users of larger instruments get to see slightly more detail. On the mornings of the 22nd and 23rd of December the Moon and Jupiter are close to each other in Virgo. The crescent moon is getting smaller each day, and on a clear morning, the unmistakable glow of earthshine will light up the ‘night’ portion of our satellite.
December Night Sky around 21.30 mid-month
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