Society for Popular Astronomy

[Alastair McBeath]

The Geminids should be getting underway by tonight, as their first meteors usually appear around December 7. However, the Moon is already past first quarter, and it will have just passed full before the shower's maximum arrives, expected next Saturday night, December 13-14, within about 2h20m of 23h UT. Sadly, the Moon will be passing through Gemini by then, a few degrees south of the shower's radiant, which lies a little way northwest of Castor, the northerly Twin-star. Consequently, both Moon and radiant will be visible all night, and will be very well on-view for UK observers by the predicted peak time. The radiant reaches a usefully-observable elevation for meteor watchers here by about 20h UT, after which it remains nicely-placed for the rest of the night, culminating around 02h.

Highest Geminid Zenithal Hourly Rates (ZHRs) should be circa 120 judging by recent returns, a strength that means something of the peak should still be readily visible under clear skies despite the Moon. Geminid rates often remain near maximum levels for 6-10 hours to either side of their best too, so December 13-14 should be the preferable night for observers braving the Moon, if the predictions hold-up. Much lower activity away from the maximum may be seen in any darker skies that manifest through to December 17. Although the shower's parent object, Apollo asteroid 3200 Phaethon (possibly a dormant or extinct comet) passed closest to Earth since its 1983 discovery on 2007 December 10, it seems not to have affected Geminid rates then (it was not anticipated it would), nor is it expected to this time.

Geminids are medium speed and often bright meteors, though few leave persistent trains after them. For those wishing to chance the Moon - and past moonlit returns do suggest the maximum should be well worth viewing even under such trying conditions, providing the sky is clear and transparent - face away from the Moon, or block it behind a convenient obstruction like a rooftop, while still observing as much clear sky as you can comfortably. More information on December's likely meteor activity, including a Geminid radiant chart, is available at: http://www.popastro.com/sections/meteor/meteor-dec2008.htm .

Remember to dress appropriately for the likely conditions - and good luck!

Alastair McBeath,
Meteor Director, Society for Popular Astronomy.
E-mail: <meteor@popastro.com> (messages under 150 kB in size only, please)

[markt]

Geminid activity has indeed started. Last night I was out observing Saturn and the local church clock struck for 3am. As the first 'gong' struck I pulled my eye away from the eyepiece and looked around the sky taking in its splendor on the crisp winters night. As the 3rd 'gong' struck a -1 / -2 magnitude white meteor shot from Gemini, through Auriga and into Perseus. Was truly a grand sight! I stayed out till about 5am before frost defeated the dew shield and started forming on the C8's corrector plate. In the 3 hours from 2am till 5am when I was observing Saturn, I saw another 3 Geminids in addition to the bright one I saw at 3am, these were 2nd / 3rd magnitude. Given my eye was fixated in the scope most of the time I was pretty pleased to see the 4 meteors and these complemented a pleasing night of astronomy
_________________
Meade 5" Refractor, ETX90, Coronado SolarMax40, C8 XLT CF CaK PST
EQ6 Pro, 15x70's, 20x80's
Canon 350D, DMK31

[andyT]

hi all,i'm hoping to get clear weather here to get some observing in.
meteors are a 'fav' of mine to watch.i would echo Alastairs comments about keeping warm too.it's been bitterly cold here in wales lately.
lets hope for some decent activity.
good luck with the watches everyone,
andy
_________________
4'' refractor
zeiss 10x50,
helios 11x80.
Leica BN 8x32,
Helios 13-40x80 bins

[david entwistle]

[Alastair McBeath]

The Geminid maximum passed behind solid overcast and continuous rain here in Northumberland on December 13-14, as across much of the country judging by the comments, and lack of comments, from many other places so far. The preliminary IMO visual results, available off the http://www.imo.net homepage, have suggested a peak rather later than anticipated, around 02h-03h UT on December 14. ZHRs may have been around the 130-140 mark, or possibly higher, but these values may have been artificially inflated in trying to correct for the bright Moon.

Those few people with good enough skies to let them report so far from Britain have suggested there were plenty of bright to minor-fireball-class meteors present in the shower on December 13-14 (up to about magnitude -5/-6, though very few significantly brighter). However, it's not clear if this was beyond what we'd normally expect. The Geminid maximum often produces a very fine crop of such meteors anyway. The Moon meant many of the fainter Geminids will have passed unseen this time, which in turn will have skewed the magnitude distributions, and people's field impressions of the shower. The radio data so far do not suggest any particularly abnormal bright-meteor activity beyond what we'd have expected from the shower, for instance.

One of the few places to report positively so far is Northern Ireland, and Martin McKenna in Co Derry there had a splendid night, imaging a number of shower meteors. Some of his better examples can be seen on the UK Weather World's Space Weather Forum "Geminids" topic, at:

http://www.ukweatherworld.co.uk/forum/forums/thread-view.asp?tid=27284&posts=1&start=1 .

Further observations would be welcomed by the Section!

Alastair McBeath,
Meteor Director, Society for Popular Astronomy.
E-mail: <meteor@popastro.com> (messages under 150 kB in size only, please)

[david entwistle]