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 ... ec2008.htm
Remember to dress appropriately for the likely conditions - and good luck!
Meteor Director, Society for Popular Astronomy.
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