The Southern Astronomer No.95 – August 2016
SOUTHERN ASTRONOMER THE
MONTHLY MAGAZINE OF WORTHING ASTRONOMERS & WORTHING SKYWATCHERS
The Southern Astronomer No.95 – August 2016
WORTHING ASTRONOMERS No fees, no Committee; just enjoying the night sky together.
F
ormed in 2008 by a group of regular and practical, hands on 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
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. 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 or photography.
Astronomy This Month
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Observing Planets
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Meteors & Comets: The Perseids
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p.5
Mercury and Venus Watching & Website News Sun Watching
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p.7
Constellation of the Month: Hercules
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p.8
Monthly Sky Map
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Cover Picture: It is August. Summer holidays. Hot days and warm summer nights (hopefully). In the country sport calendar, August 12 is known as the Glorious Twelfth when the grouse season starts.
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.
For astronomers the date is Glorious for another reason and a lot less violently. It is around this date that nature produces a firework display of its own – the Perseid Meteor shower. The number of Perseid meteors counted per hour is usually about 60 (a zenith hourly rate or ZHR) but this year the Perseid’s could be producing an extra special show with a predicted ZHR of 150.
We can be found at: worthingastronomers.org.uk
More information about this and our planned group observing to observe the event on page 5.
Contact addresses: info@worthingastronomers.org.uk – general society details Brian Halls
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 AAS can be found at Adur Astronomical Society
treasurer@worthingastronomers.org.uk – donations contact Janet Halls outreach@worthingastronomers.org.uk – events contact Steve Bassett, Mike Williams
CONTRIBUTIONS AND UNSUBSCRIBING Contributions – written articles (preferably word processed in .txt, .doc or .odt format), photographs or letters to the editor for the September issue should be in by August 15 and sent to the editor at the contact address: editor@worthingastronomers.org.uk
website@worthingastronomers.org.uk – contact for website Perry Wilkins editor@worthingastronomers.org.uk – content detail 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. 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. 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.
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The Southern Astronomer No.95 – August 2016 DEEP SKY OBJECTS
ASTRONOMY
THIS MONTH
August 2016
All times are expressed as Universal Time (UTC – Co-ordinated Universal Time) and can be considered the same as GMT (i.e. BST minus one hour.) Sunrise and sunset times over the previous month which were increasing by half an hour or so now began to increase with a difference of 44 minutes for sunrise and just over and 62 minutes for sunset over the month. QUICK VIEW DIARY 1 2 4 5 9 10 12 13 16 18 25 27 31
Sunrise 0429h : Sunset 1951h New Moon (20h) Mercury 0.6°N of Moon (21h) Workshop Evening – The Telescopes of George Ellery Hale Moon at apogee – furthest from Earth in its orbit (23h) Moon: First Quarter (18h) Perseid Maximum (02h) Perseid & Pizza Evening at the Honeysuckle Lane venue (p.5) Mercury greatest elongation East 27° (18h) Full Moon – Fruit Moon (English trad.) (09h) Moon: Last Quarter (04h) Venus 0.1°N of Jupiter(22h) Sunrise 0515h : Sunset 1853h MOON PHASES IN AUGUST
T
he August Moon – I once knew a great Chinese take-away with that name; fantastic spare ribs and a delicious set menu, but all that is another story (get on with it. Ed)– is the photogenic Moon that we witness as it rises low in the eastern sky during late summer. Often and incorrectly named the Harvest Moon (which actually occurs in September) the Moon in late Summer is, in English traditional moon-lore called the Fruit Moon due, no doubt to the time of year when the fruit harvest is gathered and perhaps the reddish strawberry or even orange hue it sometimes takes on when rising as seen through the hot summer atmospherics.
SUBJECT TYPE
Constellation
MAG
RA (h m)
DEC (° ' )
NGC6709
Open Cluster
Aquila
6.7
18 51.5
+10 21
NGC6738
Open Cluster
Aquila
8.3
19 01.4
+11 36
NGC6741
Planetary Neb
Aquila
12
19 02.6
-00 27
NGC6751
Planetary Neb
Aquila
12
19 05.9
-06 00
NGC6755
Open Cluster
Aquila
7.5
19 07.8
+04 16
NGC6781
Planetary Neb
Aquila
11.8
19 18.5
+06 32
NGC6819
Open Cluster
Cygnus
7.3
19 41.3
+40 11
NGC6826
Planetary Neb
Cygnus
8.8
19 44.8
+50 32
NGC6834
Open Cluster
Cygnus
7.8
19 52.2
+29 24
NGC6643
Galaxy
Draco
11.1
18 19.8
+74 34
NGC6779
Glob. Cluster
Lyra
8.3
19 16.6
+30 11
NGC6720
Planetary Neb
Lyra
9.4
18 53.6
+33 02
NGC6703
Galaxy
Lyra
11.3
18 47.3
+45 33
NGC6791
Open Cluster
Lyra
9.5
19 20.7
+37 51
NGC6572
Planetary Neb
Ophiuchus
8
18 12.1
+06 51
NGC6633
Open Cluster
Ophiuchus
4.6
18 27.3
+06 31
M71
Glob. Cluster
Sagitta
8.3
19 53.8
+18 47
NGC6618
Cluster & Neb
Sagittarius
6
18 20.8
-16 11
NGC6613
Open Cluster
Sagittarius
6.9
18 19.9
-17 08
NGC6494
Open Cluster
Sagittarius
5.5
17 57.1
-18 59
IC4715
Open Cluster
Sagittarius
3.1
18 26.6
-18 23
IC4725
Open Cluster
Sagittarius
4.6
18 31.8
-19 07
NGC6864
Glob. Cluster
Sagittarius
8.6
20 06.1
-21 55
NGC6603
Open Cluster
Sagittarius
11.1
18 18.4
-18 24
NGC6818
Planetary Neb
Sagittarius
10
19 44.0
-14 09
NGC6822
Galaxy
Sagittarius
8.8
19 44.9
-14 48
IC4756
Open Cluster
Serpens
4.6
18 39.0
+05 27
NGC6611
Cluster & Neb
Serpens
6
18 18.8
-13 47
NGC6604
Open Cluster
Serpens
6.5
18 18.1
-12 14
Basel1
Open Cluster
Scutum
8.9
18 48.2
-05 51
NGC6705
Open Cluster
Scutum
5.8
18 51.1
-06 16
NGC6694
Open Cluster
Scutum
8
18 45.2
-09 24
NGC6649
Open Cluster
Scutum
8.9
18 33.5
-10 24
NGC6712
Glob. Cluster
Scutum
8.2
18 53.1
-08 42
Cr399
Open Cluster
Vulpecula
3.6
19 25.4
+20 11
NGC6853
Planetary Neb
Vulpecula
7.3
19 59.6
+22 43
NGC6802
Open Cluster
Vulpecula
8.8
19 30.6
+20 16
NGC6823
Open Cluster
Vulpecula
7.1
19 43.2
+23 18
NGC6834
Open Cluster
Cygnus
7.8
19 52.2
+29 24
NGC6940
Open Cluster
Vulpecula
6.3
20 34.4
+28 17
WORKSHOP NIGHT August 5
A
different but interesting change of direction this evening – a bit of astronomy history regarding one of the pioneers of large telescope building, George Ellery Hale. The name may not be familiar to many but his telescopes probably are, so this is now a good time to find out more about this fascinating astronomer whose work was ground breaking with results that amateurs such as ourselves can use today. He even had (very tenuously) a link with a Worthing amateur astronomer.
At the start of the month the sun is still setting mid-evening and a rising Moon mid-month will be viewed by those who are making the most of the fine evening after a hot summers day (are you sure about that? Ed.) There is plenty to see in the sky this coming month. The Milky Way lays overhead, the Summer Triangle is pronounced and the Perseid meteors peak in 2016 – early on the 12th - is expected to be a particularly good display. Enjoy these fine, hot and dry summer days while you can. (You’re fired. Ed)
Make a date in your diary for August 5 – this is the night of the opening ceremony of the Rio Olympics but that will start well after the end of the meeting, so no excuse to miss this Workshop.
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The Southern Astronomer No.95 – August 2016
The planets mid-month (comparative angular diameters) – timed at 21.30UT
OBSERVING THIS MONTH:
A
PLANETS
s the year has progressed we have seen the appearance of three fine planets – Mars,
Jupiter and Saturn – which have given breath taking views to those who have been able to see them.
This month we get the last really good looks of Jupiter – mid-month it sets just about an hour after the Sun and so will be low in the south-west. In fact Jupiter, Mercury and Venus will be in a line after sunset if observed with a good horizon during the mid-month period. Mars and Saturn however will be still visible well into the evening and night though Mars’ angular diameter is shrinking and is 11” (arcseconds) in size, so a moderate to large instrument will be required to make out the detail of the planets deserts.
Visibility of the planets and Moon, mid-month
upwards) to see detail on them, even in a small telescope, their distinctive green and blue colours respectively are obvious.
With the ecliptic – the path, the Sun, planets and Moon appear to take through the sky during the year – being quite low in the summer night sky, it is not surprising that Neptune will be low but at about Mercury and Venus appear in the western sky after 30° when due south in it part of Aquarius it will be sunset and will, as previously mentioned appear not too low for observing; just a good southern sky with Jupiter for a brief period after sunset. will be required. Neptune is too faint to be seen with the unaided eye but, a pair of binoculars will just Saturn also lays in the evening and sets about make it out. midnight (summer time). Rising mid evening are the two outer gas giants, Uranus and Neptune. Though Uranus rises just over an hour later and when due these worlds require a large telescope (300mm south at around 03h UT it will be about 48° high in
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the sky in the constellation of Pisces and may under certain seeing conditions be just visible without any optical aid. With Jupiter and Saturn now beginning to disappear from our skies for the time being what is the planetary outlook for observers? The planet Venus shall over the coming months begin to brighten and become more apparent in the evening sky as the planet swings round the Sun in its orbit presenting what looks like a half moon before becoming a crescent. As it gets nearer to us the phase decreases but its angular size increases so presenting some wonderful observing opportunities during the latter part of the year.
The Southern Astronomer No.95 – August 2016
METEORS & COMETS A s it is August and as has been mentioned previously, this is the month for the Perseid Meteors the most famous and well observed of the annual streams. Before we do let us mention another meteor shower that will be visible as we will want to know which meteors we are seeing – will it be a Perseid or what? The kappa(κ)-Cygnids are a fairly recent discovery (2009) and visible from about August 3 to August 25 and will peak on August 17; a feature of this shower is the possibility of fireballs. The average hourly rate (ZHR) for this is group is 3! They appear to emanate from close to the star κ-Cygni – the star at the tip of the right wing of Cygnus. The Perseids are of course a more established shower producing a ZHR of about 60 though this year that could multiply. Astronomers Mikhail Maslov and Esko Lyytinen have calculated that this is due in part to a dense portion of the meteor stream having been nudged more towards the Earth’s orbit by the gravitational effects of planet Jupiter. Further more, another astronomer, Jèrèmie Vaubaillon, has predicted the densest part of the stream is crossed by the Earth in its orbit between 00h to 04h UT on August 12. How accurate these predictions are we really will not know until the early morning of August 12. The Perseids are normally known to be quite active in the hours before midnight on August 11 so the late night watcher may get an idea of what is happening then. We can expect the meteors to be visible well into the following evenings as well, August 12 and maybe the 13th. With that in mind it has been suggested that we have a Perseid & Pizza Evening at our Honeysuckle Lane observing venue known locally as The Sanctuary on the evening of Saturday August 13 (an idea that we have borrowed from our colleagues at Hants Astro.)
Perseids on the night of August 13
Graham Williams writes: “This would just be a general meeting to try and observe the meteor shower, (‘scopes can obviously be brought if so wished, but cameras and binoculars best.)The pizza is optional and could be ordered from a local pizza take-away on your way to the meeting site.” As we put this issue of the newsletter together this observing night is still in the planning stages but check out Facebook and the website Forum for updates www.worthingastronomers.org.uk/forum.html Bring a comfortable seat; dress to keep warm and dry (dew!); apart from the optional pizza, a warm drink and something to eat are useful to keep the body going. Perseus will be towards the north mid evening but of course, any meteors could streak anywhere across the sky. Thanks to the weekend this will be the first time we have been able to do anything like this for the Perseid’s since a successful night on Nepcote Green a few years back.
Kappa-Cygnids on August 17 Star maps by Stellarium
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The Southern Astronomer No.95 – August 2016
MERCURY & VENUS OBSERVING
T
he two inner planets appeared to come very close to each other in the evening sky during mid-July and we thought it a good idea to see if we could observe them. The night we chose was July 16 – a very close conjunction between the planets – ½° (about a moon width diameter.) As the two planets were close to the Sun the best we would get would be a short period of observation after sunset. That was of course assuming a clear view of the western sky. Naturally we were not that lucky. The previous night had been very clear as were the following two evenings but, the night we needed clear was not. David Storey got to see the two planets through binoculars and some cloud on the 16th from Honeysuckle Lane, though Linda Storey only saw Venus. Cissbury Ring Observing on the 19 th Chris Pennells (l) and Graham Williams (r)
Image: Mike Williams
Thank you to all those who did take the gamble and turned up. Interestingly the day had been relatively clear of clouds and member Bob Leggett observing from East Wittering with his 300mm guided Dob mounted Newtonian had found both planets in the ‘scope during the early afternoon (i.e during daylight!). The light back ground of natural skyglow however made it impossible to photograph. He found Jupiter a little while after as well. He certainly lives up to the nickname ‘Daytime’ Bob. Overall I think everyone had quite a bit of fun doing this even if the cloud did not cooperate. There will always be other opportunities in the future. If nothing else, these events give us a chance to meet up with our WA and Skywatcher colleagues. How better to share the night sky.
Venus(just left of centre – above the clouds) on July 20
Image: Chris Pennells
WEBSITE
A
s many of you will now be aware the groups website has undergone a massive overhaul over the last month and not only has a new look but other useful features as well.
One of these features is the Forum. I think everyone knows about internet forums and I won’t bother to go into the details of what it does – it is pretty well self explanatory. This has been bought about by the fact that not everyone ‘does’ Facebook – I didn’t up to a couple of years ago – and we needed something that all members could use to post information about observing events, cometary appearances, or any of the short notice stuff that astronomy usually generates and we need to get it out to members as quickly as possible. Sending out email alerts is a bit time consuming and I don’t always switch on the computer when I get home from a hard days work, there by some newsworthy stuff can be missed by me and is not passed on to the membership. I would like to encourage everyone – Facebook users as well – to sign up for the Forums so if you post something on Facebook can you post it in the Forum as well. That way, everyone in the group can have access to the latest Worthing Astronomers happenings! The present website is still very much under development and I would like to take this opportunity to thank Perry Wilkins who has spent quite some time over the last year or so getting to grips with Wordpress in between work, motorbiking and astronomy. I think you will agree with me that he has done a fantastic job but of course, it requires support as well. Images, snippets, use of the Forum etc are always welcome and ideas suggestions and even information about strange glitches that sometimes occur when people use different browsers and media devices. Perry’s contact details on page 2.
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Image: Mike Williams
The Southern Astronomer No.95 – August 2016
SUN WATCHING O
nce again the Sun is going through a phase of producing low sunspot numbers. The month of June ended with a number of spotless days and this continued into July. Despite the dearth of activity it did not stop members making the most of the bright sunny days observing the Sun.
Image: Chris Woodcock
Observed in the light of narrow band hydrogen alpha, Chris Woodcock observed some prominence's on the limb of the Sun, using a special solar telescope – the Coronado PST - a 12mm eyepiece and a hand held iPhone 5s. He captured these on July 23. It underlines that sunspots themselves are only just one aspect of solar activity. For a good part of the middle of the month two closely placed sunspot regions (active regions – AR) were visible. Member Brian States observing from Guildford observed the Sun on 29 days in June – another well observed month in a sequence of months where Brian has observed the Sun almost daily when ever he can. He noted that the Sun was spotless on a total of 12 days. The highest daily sunspot number was 37 on June 19. It seems that the solar longitudes that posses the strong magnetic activity to create sunspots seem to rotate onto view from about midmonth at the moment – an effect that his been noted in July.
Left: Chris Pennells caught AR’s 2567 and 2565 on July as they were progressing off of the face of the Sun. Top: Chris Woodcock caught them a few days later on July 21 as they were getting close to the western limb of the Sun.
How this will progress into August we do not know for sure but though sunspots are few the Sun remains interesting to watch.
All these images were taken in ‘whitelight’ – that is the normal light in which we humans see, though special filters were employed to deaden the glare of the bright solar image AND AT THE SAME TIME, block harmful solar radiation from getting onto the eye and causing permanent damage.
Brian’s average sunspot number for June was 13.4 which compares well with the BAA Solar Section average of 15.6; AAVSO Solar Division 16.08 and the World Data Centre of 20.9 OBSERVING THE SUN MUST BE DONE WITH CAUTION – ASK FOR ADVICE AND ENJOY LOOKING AT OUR NEAREST STAR.
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The Southern Astronomer No.95 – August 2016
CONSTELLATION OF THE MONTH: HERCULES
A
lmost overhead and a little to the south is the constellation of Hercules.
Despite being a fairly well known group of stars there are no first of second magnitude stars which comprise it though there are a number of 4m stars. Rasalgethi – α-Herculis - is a 4m binary star about 360 light years away and is an irregular variable red-giant star while the companion is a blue-green star of about 5.4m. Both stars will be visible in a small telescope or a good pair of binoculars. A more stable star is the 3m β-Herculis and is a yellow star laying about 150 light years away.
M 13
Image:Andy Li
There are not too many deep sky objects – though the globular cluster M13 (NGC 6205) can be seen with just the unaided eye or in a small telescope or even a pair of binoculars – it is about 6m. It was first recorded by Edmund Halley in 1714 and was included by Charles Messier in his catalogue during the summer of 1764. The other major DSO is also a Messier object, M92. This is also a 6m globular cluster and will again look like a fuzzy object in binoculars. It lays about 26 000 light years away. The light that is collected into your eyes when you look at this object left the cluster before human history began ; the Earth’s pole has precessed once (the northern polar point in the sky was the same then as now); and the last ice age maximum had just passed and the British Isles were probably still connected to the European mainland. There is an ‘asterism’ called the Keystone in Hercules. An asterism is a name for a group of stars in a constellation that appear to make up another shape – The Plough is an asterism in the constellation of Ursa Major for example.
when compared to the star charts of the ancients. The celebrated artist H A Rey in his book, A New Way To See The Stars redrew the constellation and had the Keystone appear as Hercules head, Rasalgethi the left foot and some of the minor stars in the constellation making up more prominent characteristics of a charging man with a club – the way I think of a strong character like Hercules, taking no nonsense from anyone. There are many stories about Hercules in mythology and the character of a hunting man appears to go back well before the Greeks turned him into a well known Hero.
It is believed that to the ancients of Mesopotamia he was a Standing God with the feet of a serpent From the IAU chart above, the Keystone is quite an (crocodile shoes anyone?) obvious feature. The fact that the constellation of Draco The Dragon Interestingly the star Rasalgethi, means ‘head’ and (or serpent is nearby) would give credence to the our depiction of Hercules is actually upside down story.
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H A Rey’s realistic depiction of Hercules is more recognisable for what it is supposed to be.
The Southern Astronomer No.95 – August 2016
Graphic: Stellarium
An all sky view in mid August at about 21.30 UT
T
he Milky Way still dominates the mid evening and night time sky. The Summer Triangle asterism is on the meridian mid-evening, Deneb in Cygnus, Vega in Lyra and, Altair in Aquila the three bright points of the Triangle.
Towards the low southwest Mars and its doppelganger Antares (see last months issue) form another triangle in the sky with Saturn. In the opposite portion of the sky – the north-east – Perseus is rising and will be the target of sky watchers every where who will want to try and catch a glimpse of a possible enhanced Perseus meteor display during the mid-month period. To the east and also rising is the double constellation of Pegasus and Andromeda who, in mythology, have a story associated with Perseus. The furthest most object one can see with their naked eye is rising among those star patterns – the Andromeda Galaxy M31. We’ll be speaking a little more about M31 in the coming months as it is a favourite target for experienced and novice astro-photographers alike and its view through binoculars and small telescopes alike is something not to be missed. Almost flying overhead is Cygnus, The Swan. Laying in the Milky Way the constellation is a fine object to scan with binoculars on a summer evening. For astro-imagers it is the home of NGC 7000, the North America Nebula. Let us hope for fine weather and clear skies.
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