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(meteorobs) Meteor Activity for December 11-17
This period will be dominated by the Geminid meteor shower. The
Geminids, which produce medium speed meteors, will peak in activity
Monday evening/Tuesday morning December 13/14 for most areas. Rates
should approach and perhaps surpass 100 Geminids per hour near 0200
local time from rural sites far from light pollution. On the night of
maximum activity the radiant is very close to the bright star Castor in
northern Gemini. It rises between 1800 and 1900 local time for most
areas. At this time there is the possibility that earthgrazing Geminids
can be seen shooting up from the northeastern horizon. Most of these
meteors seem to hug the northern or southeastern horizon rather than
shoot straight upwards. These "earthgrazers" are quite long and last
several seconds. Unfortunately most of them are not bright and the moon
in the western sky may obscure some of these meteors. It is still worth
the effort to see these meteors if you are limited to watching during
the early evening.
As the night progresses the radiant rises higher into the eastern sky
and the meteors will become shorter and will appear to be shooting in
all directions including straight down. The moon will be setting into
the west allowing more activity to be seen.
By 2300 local time the moon should have set and the Geminid radiant is
now high in the eastern sky. Rates should now be one per minute with
activity being seen all over the sky. By 0200 the radiant will be nearly
overhead and activity should be at maximum strength. I have seen up to
144 Geminids per hour at this time, often with simultaneous meteors
occurring. At this time you should be facing your darkest direction at
least halfway up in the sky so that you can see the most activity
possible.
By 0400 local time the radiant is still high in the western sky but
rates will have dropped to perhaps 50-60 per hour due to the reduced
altitude of the radiant. If one watches from 2300 to 0500 from a rural
site free of light pollution there is a good possibility that you could
see 500 meteors during this 6 hour period.
While watching the Geminids you will also notice other activity with
differing velocities coming from other areas of the sky. Most of these
are probably sporadic meteors (random) but there is the possibility that
they could belong to one of the minor showers active at this time. The
following is list of possible minor activity you may see:
The Chi Orionids have a radiant in the "foot" of Gemini near M35. I
would only expect to see 1 or 2 per hour of these medium-slow meteors.
They are best placed for observing near midnight.
The Puppid-Velids have a radiant very low in the southern sky. These
meteors are just a bit faster than the Geminids. If you happen to see a
long lasting meteor shooting up from the southern horizon it is a good
chance it belongs to the Puppid-Velids. Unfortunately these meteors are
rare from north temperate latitudes with only 1-2 being seen each night.
You best chances to see one of these meteors occurs near 0300 local
time.
The Monocerotids have a radiant between the bright stars Procyon and
Betelgeuse some 20 degrees south of the Geminid radiant. Being this
close to the Geminid radiant presents a problem for any Monocerotid
traveling southward as the path could trace back to either radiant.
Chances are it would be a Geminid if seeing moving in this direction.
You could be more positive of it being a Monocerotid if it travels in
any other direction. The Monocerotids are a bit faster than the Geminids
but this is difficult to compare unless you are experienced at
estimating angular velocities. The Monocerotids are best placed near
0100 local time producing perhaps 2-3 meteors per hour.
The Sigma Hydrids are swift meteors coming from the "head" of Hydra,
located just south of Cancer and the "Beehive" cluster. These meteors
are swift and often leave persistent trains which should aid with
identification. The radiant is best placed on the meridian near 0300
local time. Expect to see 3-5 of these meteors per hour.
The Coma Berenicids are just now beginning to become active. These
meteors are extremely swift with most shower members having persistent
trains. I have also noticed that most Coma Berenicids also have a blue
color. This radiant lies in east-central Leo and is highest in the sky
just before dawn. Rates should be 2-4 per hour. There have also been
reports of swift meteors coming from the "Sickle" of Leo at this time.
Some observers refer to these meteors as December Leonids. It is not
certain if this radiant is fact or if these December Leonids are
actually Coma Berenicids appearing at the edges of one's field of view.
Late in the morning you might keep an eye out for this activity and
decide for yourself.
Finally some tips on observing this week. If you are limited to watching
during the evening hours then face eastward toward the constellation of
Taurus. This will minimize the impact of the moon and let you see
activity from the Chi Orionids, Geminids, and the Monocerotids.
If you are watching in the middle of the night place your center of view
near the bright star Procyon in Canis Minor. This will allow you to view
most of the radiants in your field of view which will help with shower
association.
Late morning observers could center their field of view high in the
southwest sky for the same reasons as mentioned above.
Be sure to bundle up and keep warm! Also remember to visit Geminids.com
and http://comets.amsmeteors.org/meteors/showers/geminids.html
for more information. I look forward to reading all your reports!
Best Wishes for Clear Skies!
Robert Lunsford
AMS Visual Coordinator
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