Saturday, 2 August 2014

Perseids, ISS, Supermoon, AP, Rosetta, INAM, Solar Day @ WWT, 2 Newgrange events

Hi all,
The Perseids are one of the best, and usually the most popular, of the annual meteor showers. The shower gets underway at the beginning of August, and peaks on Aug 12 or 13: this year it's at 0h on the 13th. Normally that would give us ideal observing conditions, but this year the view will be spoiled by a bright Moon, just past Full (it will actually be a 'SuperMoon', see below. So some of the best views may be over the next few days, before the waxing crescent Moon gets too bright - First Quarter will be on 4 Aug at 01.50.
  But on the night of maximum it will still be worth looking, even though all but the brighter meteors will be drowned out by the moonlight - try to get a view of the sky where the Moon is hidden by trees or a building etc.
   The radiant will be high in the sky late in the night, near the famous Double Cluster in Perseus, but you can see the meteors in any part of the sky. Usually it's best to look at an area about 50 degrees above the horizon, and about 50-60 degrees from the radiant - avoiding direct moonlight if you can.
  The shower persists to about August 16/17, but with gradually declining rates. On the succeeding nights (13/14, 14/15 and 15/16) it would be worth looking in the brief but lengthening interval between the end of twilight, and Moonrise.
2. ISS VISIBLE AGAIN: The ISS is now visible in morning skies, until 3 August, from when the passes will be visible both before and after midnight until mid-August. From then, it will be visible in evening skies until 21 August.
3. BEST SUPERMOON, August 10:
This phenomenon has caught the attention of the media in recent years, although the visual effect has been greatly overhyped by them. Still, you might as well be informed. A Supermoon occurs when Full Moon occurs at, or very close to, the Moon's perihelion, i.e. when it's close to Earth in its elliptical orbit (eccentricity of 0.0549). The Full Moon will therefore appear a bit bigger and brighter than usual.
  The variation in distance can be quite significant: at its closest to Earth the distance is only 356,410km; at max it can be 406,697km, a difference of 50,287km.

   That means that its apparent size as seen from Earth varies from 33' 31" to 29' 22". That's a difference of 30% in apparent area, or that it's almost 205 square arcminutes bigger when at extreme perigee than at extreme apogee. And of course the brightness will increase by even more than that since the brightness varies with the inverse square of the distance. 

   The experts will know that there are actually five astronomical definitions of a month (as well as the civil ones). The two of interest to us are the -

1. Anomalistic: (apse to apse, or perigee to perigee): 27d.55455. This can vary in length by several days.

2. Synodic: (New Moon to New Moon) = 29d.53059. This can currently vary by up to 7 hours.  

  If the anomalistic and synodic months were the same length, then we would have perigee at the same phase of the month each time, at least on average. But because of the average difference of 1.97604 days, the date and time of perigee moves backward through successive months at an average of just under 2 days per synodic month. E.g. forthcoming perigees are: Aug 10d 17h 42m; Sep 8d 03h 00m; Oct 6d 09h 38m, Nov 3d 00h 28m. 

  So what gives us our Supermoons? Remember, we're looking for a perigee to occur as close as possible to the date and time of Full Moon. There's no standard definition, but the popular websites, magazines, etc, seem to agree that if they occur on the same date then that's a Supermoon. But you could have perigee at 00h 00m, and Full Moon on 23h 59m, giving a gap of almost a full day. Alternatively, you could have Perigee on, say, May 31d 23h 59m, and Full Moon on June 01d 00h 01m, giving a Supermoon even though the two events occur on different days, indeed in different months, although the time difference is only 2 minutes! So I would use a working definition of a separation in time by no more than 12h, irrespective of the dates.

   But of course, not all perigees are equal. For example, in 2014, the least close perigee occurs on Nov 27 at a distance of 369,827km. That's 12,932km more distant than the perigee on 10 August. So for a really super Supermoon, we want a really close perigee, and for it to occur as close as possible to Full Moon.

   And for us to see it at its best, it also needs to happen when the Moon is above our horizon, otherwise the distance will have increased a bit (and the Moon will no longer be exactly 'Full') by the time the Moon rises. 

   Ideally, it should occur at the time the Moon is highest in our sky, i.e. transiting the S meridian. And for the absolute best circumstances, it should occur when the Moon is overhead for the observer. If the Moon is overhead, you are about an Earth radius closer to it than when it is on your horizon: that's about 6370km.


   The one on August 10 this year is quite good: it's the closest perigee of the year, at 356,895km. And it occurs only 27 minutes before Full Moon. But FM occurs at 19.09 BST, which is 1h 22m before Moonrise in Belfast, at 20.31 BST. That is not too bad, but it means that by the time the Moon transits here at 01.39 next morning, it will be a little further away, at 356,977km from the centre of the Earth. But the reduced distance from us here in Ireland as it transits, will more than make up for that. However, it will also be even more past Full.

   Still, it will give us near perfect conditions to see a Supermoon combined with the Moon Illusion, which makes the Moon appear much larger when it's close to the horizon. It's only a psychological effect, but a very powerful one. So the rising moon on the evening of 10 August should appear really big.

   I've done an article for the next issue of STARDUST going into this all in more detail, but to summarise, the one on 10 August will be roughly equalled by one on 2016 Nov 15, but it won't be bettered until 2018 Jan 1. 

4. August events at Armagh Planetarium:
Including: 6 starshows daily; The Great Balloon Race, Sat 2 & Sun 3 August; Make your own Pinhole Camera, Friday 15 and Saturday 16 Aug; Astronaut sculpting classes, Sat 23 & Sun 24; Force Academy Training, Sat 30, Sun 31. See their website for full details
5. ROSETTA nears Comet. The Rosetta spacecraft is rapidly (well, actually slowly!) closing in on Comet Churyumov-Gerasimenko, which it will start to orbit on August 6. After studying the 'binary' surface in more detail, it will land a probe on the surface. Watch out for some amazing photos.  See
6. Major astronomy event in Dublin, INAM: 13-15 August: REGISTER NOW:
You should register even if you only want to attend the public lecture.
Details: This year the ASGI is proud to announce the first Irish National Astronomical Meeting (INAM:2014), celebrating the 40th anniversary of the ASGI, and spanning 3 days. This will represent the new format of the future ASGI meetings, with more focused sessions, chosen by the Irish Astronomical community, aimed at developing meaningful and long-lasting collaborations and friendships. 
* We invite you to join us at the Hamilton Conference Centre on the main Trinity College Dublin campus, between August 13th – 15th.
* Full details are at the meeting website, but we highlight some key points here:
* Deadline for registration is 13th July 2014. There is no registration fee.
* Abstract submission and registration are handled on the website.
* The website provides information on travel and accommodation options.
* The ASGI intends on awarding a number of small grants of approximately €100 (or equivalent in GBP) to help support travel/accommodation costs of PhD students and young researchers from outside the immediate Dublin area.
* In addition to the scientific programme of 5 thematic sessions, the meeting will also feature an evening public lecture by Professor Paul Roche (University of South Wales), a conference dinner, and the inaugural INAM football tournament!
Register at
   NB: This is a professional level event (apart from the public lecture), so be prepared from some fairly advanced maths and physics! T.M.
7. IAA Solar Day, WWT, Castle Espie. We will be holding another one of these very popular events on Sunday afternoon, 17 August, from 2.00 to 5.00. We will have solar observing (if clear), telescope displays, exhibition, meteorites, and of course the ever-popular starshows in the mobile stardome, courtesy of Armagh Planetarium. Book your attendance at the starshows at the WWT website.
8. Special IAA Event at Newgrange for Heritage Week, 31 August: The IAA is privileged to have been invited to run a unique observing event at Newgrange World Heritage Site to mark the end of Heritage Week in Ireland. We will have telescopes at the actual Newgrange Mound to observe the sky, which as far as is known has never been done before. In the event of bad weather, visitors will be given a special tour inside the Newgrange Mound. Details and booking must be made direct with Bru Na Boinne, at  See also
 More details on times, access etc, in next bulletin.
9. ASTROARCHAEOLOGY TRIP TO NEWGRANGE and KNOWTH: Following the success of last years' trip, Stranmillis University College Institute of LifeLong Learning have asked to run another one, on 11 October, but this time including a visit to the Knowth Tomb as well. It has the largest collection of Megalithic art anywhere in Europe in one single site, some of which is reckoned to be astronomical. Booking for thus very popular, non-technical trip, is via the Stranmillis website, or go direct to,456138,en.pdf and scroll down to p. 23, or pick up a brochure from Reception.
10. The Skelligs Star Party 2014, Taking place from Skelligs Lodge, Ballinskelligs Co Kerry on Aug 22nd to Aug 24th. Chosen as it is within the Kerry Dark Sky site.  Meeting Friday 22nd Aug at Skelligs Lodge from 7pm.… Here is the link to Skellig Lodge:
We will have a few speakers and workshops on Saturday 23rd Aug from 1pm.…
Stephen Kershaw of Ktec Telescopes plus Carl O'Beirnes of Scopes and Space
Will be bringing a few astronomy goodies for us all to drool over.
I have set up a few events pages here are the links:
Kind Regards, Roy Stewart
11. EXCLUSIVE: Visit to Andor Technology Camera Facility, 13 September: The IAA has arranged a special visit to the Andor Technology Camera manufacturing facility in Belfast. As many of you will know, Andor make some of the best - in many cases the best - high-end digital cameras in the world. They are used in every scientific application imaginable, including of course astronomy, and they can be found in many of the world's top observatories, and in spacecraft. They are also moving into the range of amateur astronomers, having recently acquired Apogee Instruments. Thanks to Dr Andy McCrea we have arranged a free special visit for IAA members, and friends, to this facility, on Saturday 13 September.
Provisional Programme:
1200 Meet in Andor Reception
Introductory welcome and short talk
Lunch (Free, provided by Andor) in their canteen
Tour of the Clean Room and factory assembly floor
Talks on the range of cameras and their applications
Talk on solar astronomy imaging using Andor cameras by Prof Mihalis Mathioudakis of the Astrophysics Research Centre in QUB (link from QUB/ Professor Smart)
Q&A Discussion
Finish - say 1530
  This is an exceptional opportunity to see and learn all about the latest developments and future plans for top class astronomical imaging equipment. Andor will also be interested in feedback from expert amateur users of digital imagers, so this is your opportunity to let them know what YOU would like to see available.
   Spaces are limited, so you must register your intention to attend. Please send your name and contact details to Dr Andy McCrea (of North Down Telescopes: email to ensure that you get a place, and mark your diaries now!
12. IAA ASTRONOMY VISITS - PLANS: As part of our 40th Anniversary celebrations, we are planning at least one astronomical trip to either GB or Paris. This is a preliminary enquiry to assess where the main interest would be. The options are broadly as follows: They would be in the form of a long weekend trip (Friday - Sunday, or Saturday to a BH Monday, or possible Friday to Monday)
1. GB Trip A: Visit to Jodrell Bank, The National Space Centre at Leicester, and possibly either the Spaceguard Centre in Wales or the astronomy centre at Cambridge.
2. GB Trip B: Visit to the historic Greenwich Observatory, Science Centre and Planetarium in London + a visit to the Royal Greenwich Observatory site and Science Centre at Herstmonceux in Sussex, + a visit to the South Downs Planetarium in Chichester (headed by Dr John Mason)
3. Trip to Paris: Visit to Paris to see the historic and still functioning Paris Observatory (made famous by Flammarion & others), and the Meudon Observatory near Versailles, just outside Paris: this hosts the famous 33" 'Grand Lunette' Refractor, the 3rd largest refractor in the world, and the largest outside the USA.
   If you are interested in any of these trips, please let me know by return, indicating them in order of preference.
13. INTERNATIONAL METEOR CONFERENCE, 2014  Thursday September 18 till Sunday 21 September 2014, Giron, France. Giron is a small village located in the south of the Jura Mountains close to Geneva. The region is easily reachable by air (Geneva or Lyon airport), by train (TGV high speed train from Paris and InterCity trains from Geneva railway station) and by car (highway A40 Lyon-Chamonix). Part of the attraction for this event is that a free visit to CERN is included in the price! See
 After 30 June you will not be able to book extra nights before or after the IMC via the LOC. After 30 June extra nights should be booked on your own behalf.
14. New Scientist Live Lecture, London: How the universe began - 19 November, with: Prof Lord Martin Rees, Astronomer Royal, Emeritus Professor of Cosmology and Astrophysics, University of Cambridge.
A second speaker to be confirmed.
   The recent discovery that the cosmic microwave background also bears the scars of gravitational waves - the squeezing and stretching of space time itself - is enabling us to build an increasingly detailed picture of the birth of the universe.
(A very limited number of tickets are available for this lecture) If you are going to be in London then, this might be worth attending
Galway Astrofest: Feb 21, 2015, Theme: "New Worlds - New Horizons" Excellent speaker line-up already!  See
 COSMOS: April 17th to 19th 2015, Shamrock Lodge Hotel, Athlone.
The chances of finding anything are VERY remote. And as for that illustration, (1) it's an asteroid, not an Earth-origin meteorite. (2) That one would never make it to the Moon anyway - since either E or W is to the right (shown by the sunlight on the Moon), that one is going in the wrong direction. (I hope they don't make the same mistake with the mirror as NASA did....) This won't really be a quantum leap forward: it will only have 50% more light grasp than the JWST. It will probably have better instrumentation, however.
30-metre telescope stars construction Thirty metres! When I started in astronomy, the second largest telescope in the world was 3 metres in diameter (the 120" reflector at Lick Obs), and the largest was 5 metres (the 200" at Palomar). And site work for the 39-metre E-ELT is underway in Chile.
17. TWITTER: Follow the IAA on Twitter: The account is now operational again as before: @IaaAstro.

18. JOINING the IRISH ASTRONOMICAL ASSOCIATION is easy: This link downloads a Word document to join the IAA.
    If you are a UK taxpayer, please tick the 'gift-aid' box, as that enables us to reclaim the standard rate of tax on your subscription, at no cost to youYou can also make a donation via Paypal if you wish: just click on the 'Donate' button.  See also
Finally, in tribute to the late great John Dobson, a quote from him which is typical of the man, and very appropriate:  "If you figure something out for yourself, it doesn't make no never-mind who figured it out first, it's yours."
Clear skies,
Terry Moseley

No comments: