Active 7-16 December
Radiant RA 07h32m Dec +33^o

Currently the most active of the regular annual showers, with rates outstripping those of even the Perseids for a 24-hour interval centred on their 13-14 December maximum, the Geminids are a real treat for observers prepared to brave the winter cold! Unusual in being associated with an asteroid - (3200) Phaethon - rather than a comet, the shower has grown in intensity since the 1980s as a result of the meteor stream orbit being dragged gradually outwards across that of the Earth. A consequence is that we currently encounter the most densely-populated parts of the meteor stream. This happy situation is temporary unfortunately - in a few more decades, Geminid displays can be expected to diminish in intensity. Here we have an excellent opportunity to follow, year on year, the evolution of a meteor stream.

Geminid meteors enter the atmosphere at a relatively slow 35 km/sec, and thanks to their robust (presumably rocky/asteroidal as opposed to dusty/cometary) nature tend to last longer than most in luminous flight. Unlike swift Perseid or Orionid meteors, which last only a couple of tenths of a second, Geminids may be visible for a second or longer, sometimes appearing to fragment into a train of ‘blobs’. Their low speed and abundance of bright events makes the Geminids a prime photographic target.

Activity is expected to peak around Dec 14d 11h UT - during UK daylight. The maximum is broad, however, and observations on the Thursday night to Friday morning of Dec 13-14 should be productive even ahead of peak, especially late on in the night when the radiant  (just north of Castor) is high in the sky - see table below. The evening of Dec 14-15 is also likely to be graced with high Geminid activity, with the added bonus of an increased proportional abundance of bright events. Past observations show that bright Geminids become more numerous some hours after the rates have peaked, a result of particle-sorting in the meteor stream. The interval during which the brightest Geminids typically occur coincides with the early evening hours of Dec 14-15 at UK longitudes: under similar circumstances in 2003, several spectacular Geminids were seen.

Local Time    Radiant Altitude (53^oN)     Local Time    Radiant Altitude (53^oN)

20h                                    25.4^o                     00h                          60.5^o

21h                                    34.1^o                     01h                          67.1^o

22h                                    43.1^o                     02h                          70.0^o

23h                                    52.1^o                     03h                          67.4^o

In recent years, the Geminids have shown typical peak observed rates of 50-60 meteors/hr in good skies. Wrap warmly and enjoy the show!