(meteorobs) Meteor Activity Outlook for December 21-27, 2007

[Robert Lunsford]

No matter where you live, the first half of December provides some of the
best meteor activity of the year. In the northern hemisphere the sporadic
rates are still strong plus you can also count on strong activity from the
Geminids, which peak on December 14. There are also several minor radiants
that add a few meteors each hour. All of these centers of activity are
located high in the sky during the early morning hours this time of year.
The night of December 13/14 is no doubt the best night of the year to view
meteor activity. The moon is favorable during this entire period. After the
15th, the shower activity suddenly wanes and a great majority of the
activity seen is sporadic. Approaching Christmas the moon become a major
factor and ruins the maximum of the Ursid shower.

As seen from the southern hemisphere the sporadic rates are increasing
toward a January maximum. Shower rates are also good but the Geminids suffer
a bit from the lower elevation seen from southern locations. Still with the
warmer weather now occurring south of the equator, December is a great time
to view celestial fireworks.

During this period the moon reaches its full phase on Monday December 24.
The moon will remain a major factor during this entire period obscuring all
but the brightest meteors. The sources of meteors listed below are active
during this period but will be difficult to observe this week due to the
lunar glare. If your sky is transparent and the limiting magnitude exceeds
+5.0, then you may be able to achieve some success. The estimated total
hourly rates for evening observers this week is two from the northern
hemisphere and one from south of the equator. For morning observers the
estimated total hourly rates should be near seven from the northern
hemisphere and four from the southern hemisphere. These rates assume that
you are watching from rural areas away from all sources of light pollution.
The actual rates will also depend on factors such as personal light and
motion perception, local weather conditions, alertness and experience in
watching meteor activity. Rates are reduced this week due to intense
moonlight.

The radiant positions and rates listed below are exact for Saturday
night/Sunday morning December 21/22. These positions do not change greatly
day to day so the listed coordinates may be used during this entire period.
Most star atlases (available at science stores and planetariums) will
provide maps with grid lines of the celestial coordinates so that you may
find out exactly where these positions are located in the sky. A planisphere
or computer planetarium program is also useful in showing the sky at any
time of night on any date of the year. Activity from each radiant is best
seen when it is positioned highest in the sky, either due north or south
along the meridian, depending on your latitude. It must be remembered that
meteor activity is rarely seen at the radiant position. Rather they shoot
outwards from the radiant so it is best to center your field of view so that
the radiant lies at the edge and not the center. Viewing there will allow
you to easily trace the path of each meteor back to the radiant (if it is a
shower member) or in another direction if it is a sporadic. Meteor activity
is not seen from radiants that are located below the horizon. The positions
below are listed in a west to east manner in order of right ascension
(celestial longitude). The positions listed first are located further west
therefore are accessible earlier in the night while those listed further
down the list rise later in the night.

The full descriptions of each active meteor shower will continue next week
when the moon becomes less of a nuisance to observers. It should be noted
that the Ursids may produce a short outburst near 21UT on the 22nd. This
timing favors Europe, Asia, and the northern polar regions.

Antihelion (ANT) - 06:56 (104) +22
Northern Hemisphere - 2   Southern Hemisphere - 1

Coma Berenicids (COM)  11:56 (179) +23
Northern Hemisphere - 1   Southern Hemisphere - <1

Ursids (URS)  14:28 (217) +75
Northern Hemisphere - <1   Southern Hemisphere - <1



*For a detailed explanation on the different classes of meteor showers and
other astronomical terms, please visit:
http://www.amsmeteors.org/showers.html#2007

Clear Skies!
Robert Lunsford
American Meteor Society