Sunday night marked the predicted peak of this year’s Geminid meteor shower. Observers from around the world submitted observations to the International Meteor Organization. These observations showed that a possible double peak was observed on Dec 13 at ~18 UT and on Dec 14 at ~1 UT. At its best the Geminids produced ~130 meteors per hour (assuming a dark site where stars as faint as magnitude 6.5 could be seen and the radiant was overhead). The measured peak rate may change with further analysis. If the ZHR of 130 per hour holds then this year’s Geminids were pretty much as strong as predicted. Some predictions called for the peak to occur on Dec 14 at 5 UT so the actual peak was a few hours early.
The 2 graphs below are from the International Meteor Organization. The first shows the hourly rate of Geminids for the past 11 nights. The 2nd focuses on the peak of activity.
Graph of Geminid ZHR rates centered on the time of the peak. Credit: International Meteor Organization
Here in Tucson something other than meteors was falling from the sky. The clouds and rain kept me from observing. Still I left my 2 cameras on and they were able to detect 7 meteors between the clouds. This is the 2nd year in a row that the Geminids have been clouded out for Tucson. Not too far to the south of Tucson in Hermosillo, Salvador Aguirre had better luck. On the night of the peak he observed 33 Geminids. Even better was his tally for the night before the peak when he observed 260 Geminids including 21 Geminids seen in a single 15 minute span.
Last night the sky was clear once again though Geminid activity has greatly decreased from the night before. 2010 will be another great year for the Geminids. Though the Moon will be a problem until around midnight. After that the sky will be nice and dark.
From Bob’s note for the night of Dec 14/15 : “After a week of clouds and rain the sky finally cleared. There was still a thin layer of high clouds which seemed to affect the sporadic count more than any of the showers. At 11:51:20 UT (3:51:20 am PST) a Sigma Hydrid fireball estimated at magnitude -7 was captured in the northeastern sky passing just east of the Big Dipper.”
A -7 magnitude Sigma Hydrid from Bob Lunsford camera on Dec 15 @ 11:51:20 UT. Credit: Bob Lunsford
Obs Date(UT) Time TOT SPO ANT GEM HYD MON PUP DAD DLM COM
TUS 2009-12-15 12h 07m 58 23 2 18 6 0 0 1 7 1
SDG 2009-12-15 12h 00m 71 33 6 16 5 2 0 0 7 2
TUS 2009-12-14 02h 17m 7 2 1 4 0 0 0 0 0 0
TUS - Camera in Tucson operated by Carl Hergenrother
SDG - Camera in San Diego operated by Bob Lunsford
TotTime - Total amount of time each camera looked for meteors
TOT - Total number of meteors detected
SPO - Sporadics (meteors not affiliated with any particular meteor shower)
ANT - Antihelions
GEM - Geminids
HYD - Sigma Hydrids
MON - Monocerotids
PUP - Puppids/Velids
DAD - December Alpha Draconids
DLM - December Leonids Minorids
COM - Coma Berenicids