Viewing the Geminid Meteor Shower in 2011

The Geminid meteor shower normally provides the strongest display of meteor activity each year. Unfortunately, this year, like many of the other major annual showers, the Geminids will be compromised by a bright moon. Activity from this source may be first noticed near December 4th when the radiant lies in north-central Gemini. At this time the moon will be a waxing gibbous phase, lying among the stars of the constellation Pisces. It will set near 0200, allowing good conditions to prevail the remainder of the morning. The moon will set approximately one hour later with each passing night so the window of opportunity quickly disappears. After December 8th, the moon will remain in the sky most of the night. This is around the time the Geminid rates begin to rise but the full moon will temper any increase.

Rates will kick into high gear on the 12th, when the 93% illuminated moon, located in eastern Gemini, rises near 1900 (7pm) local standard time. Under better conditions one could normally count up to 40 Geminids each hour on this night. With the bright moonlight though, one would be lucky to see 10. The Geminid peak will occur on the night of December 13/14, with the 86% illuminated moon located in the constellation of Cancer. The moon will rise near 2000 (8pm) LST and will allow the observer approximately two hours of observing under dark skies before moonrise. Even under these good conditions, the low elevation of the Geminid radiant will limit rates to approximately 20 meteors per hour. I would expect rates to remain near this figure through the early morning hours as the bright moonlight will offset the high elevation of the Geminid radiant. Under transparent skies, one may reach 30 Geminids per hour when the radiant lies overhead between 1-2am on December 14th. After this hour I would expect rates to fall as the Geminid radiant loses elevation in the western sky and the moon culminates high in the south.

Geminid rates quickly fall after maximum activity and the following night will offer only a small fraction of the activity seen previously. The Geminids disappear altogether after December 16th.

The best strategy for viewing the Geminids this year would be to face in a direction away from the moon, about half-way up in the sky. While brightness and length will be different for each meteor, all Geminids will have a similar velocity and direction if you stay faced in one area of the sky. If the moon has not yet risen, then face toward the east and watch for long trailed Geminids shooting upwards from the northeastern horizon. Early in the evening, most of these meteors will stay low in either the north or south. But occasionally one will shoot straight upwards, giving a fine view of these meteors. Once the moon has risen, then change your field of view to avoid the direct moonlight.

Near maximum activity, the Geminid radiant is very easy to find as it lies close to the bright star Castor, in the constellation of Gemini. The Geminids are slower than most major annual showers therefore bright meteors often last longer than your typical meteor and can display some fragmentation. The Geminid shower produces a fair share of fireballs with some of these meteors displaying vivid colors.

Don’t waste a clear night near the Geminid peak! Even though the moon will spoil the show, the Geminids still have the capability to outperform all but the Perseids and Quadrantids at maximum activity despite the lunar interference.

Tags: 2011 Geminids December Major Annual Showers Geminid Meteor Shower

Robert Lunsford

Bob has been interested in the stars as far back as he can recall His first experience with meteors was a biggie, the 1966 Leonid shower. In 1980, a major awaking occurred. He received a sample copy of Meteor News. He was amazed to learn there was a group actually devoted strictly to meteor observing! He joined the group also started to view some of the minor showers list among the pages of Meteor News. Lastly, he was contracted by Springer Publishing in 2007 to write a book on observing meteors. The book is now available and hopefully will be a useful guide to all interested in the enjoyable field of meteor observing.