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(meteorobs) Re: NWM2000Dec13/14 bright colorful Geminids
What a difference one day makes. A cloud group went by in the first hour of
darkness when the Geminid radiant had not risen yet. The rest of the night
was completely clear and mild. Joan and I went out to begin observing about
9 PM. I decided to skip the first hour -- not having any luck with
earth-grazers in recent years anyway. The sky was surprisingly good with
the moon so bright, still managing LM 5.5 until we quit. The only problem
was a moderate number of mosquitoes activated by springlike temperatures.
We had a nice refreshing breeze the first couple of hours which helped to
unbalance the bugs, but when the breeze died we had to fan ourselves. The
cardboard fans went limp from saturation humidity by the end. Joan gets
chllled easily, so that plus the bugs forced her to stay in the car our last
45 minutes. For partial bug relief and alertness maintenance I did the
last half hour standing up. slowly walking, and stretching.
The bright Geminids came right on schedule. Pacific longitudes were not
part of my expectation, as Mike Linnolt's note confirms,
>I had high hope of seeing a fine show tonight, the "peak"
>night with the supposed "fireballs".
The bright ones become very dominant during the rapid decline in overall
rates. They continue declining, then fainter ones again take over as
stragglers for a couple more nights. In the later hours the rates are
really falling off. Dec 14/15 I would expect little to be seen with the
moon interfering this year. This was my 7th leap-year view of the Geminids,
and it has yet to vary. The Pacific quadrant next year will get what I saw
this year.
The Geminid activity curve is asymmetrical. It takes 4 days to build up,
but less than 2 days to decline.
I observed 858 PM - 130 AM EST (158 - 630 UT) in sky LM 5.5 throughout. It
was getting ready to drop to 5.0 before the moon moved overhead, and with
rates acting like the severe decline was setting in, we decided to quit.
There were 78 meteors recorded in 4:32 hours : 68 Geminids, 1 Monocerotid, 1
Sigma Hydrid, 1 South Chi Orionid, and 7 sporadics. (Joan counted 50
undifferentiated meteors.) I saw one casual -2m Geminid seen from the car
as we neared the observing site. The four regular hours 926 - 126 EST (226
- 626 UT) had 21,19,8,16 Geminids and 0,2,2,3 sporadics. December evenings
are very slow for sporadics, and these don't improve much until after 2 AM.
Without the Geminids the sky would be almost dead.
Geminid magnitudes in the range -2m to +5m : 3,12,19,4,14,7,5,4 ; total 68,
average 1.10m. The last 11 Geminids were a colorful blaze of glory : a lone
+4m, five 0m's, and five -1m's. That helped exaggerate the curious lack of
first-magnitude Geminids. No fireballs were seen from this location. Not
every year has them.
There were 44 colored Geminids, including 3 casuals. Color totals were 21
yellow, 2 orange, 8 blue, 4 green, 1 white-green, 3 blue-green, 1
green-blue, 1 white-yellow, and 1 white-blue. The only time I get to see
several green meteors in one night comes during the Geminids.
After getting back home we went for the usual one-mile dog walk around the
neighborhood. I saw 2 casual Geminids shortly after we started, Joan missed
them both, and that was the last for the night. Accumulating roughly half
an hour of casual watching brought no more meteors at all. So we had quit
at the right time.
Norman
Norman W. McLeod III
Staff Advisor
American Meteor Society
Fort Myers, Florida
nmcleod@peganet.com
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