(meteorobs) Meteor Activity Outlook for January 12-18, 2007

[Robert Lunsford]

January sees a peak of sporadic activity for the southern hemisphere while
rates seen north of the equator begin a steady downward turn that continues
throughout the first half of the year. The sporadic activity is good for
both hemispheres, but not as good as it was for northern observers in
December. Once the Quadrantids have passed the shower activity for January
is very quiet.

This week the moon wanes from a last quarter phase and will be a day before
new at the end of the period. Some slight lunar interference will occur this
weekend from the waning crescent moon but this can been easily overcome be
viewing in a direction away from the moon. By early next week the moon will
not be a factor at all. The estimated total hourly rates for evening
observers this week is near four no matter your location. For morning
observers the estimated total hourly rates should be near fifteen no matter
your location. 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.

The radiant positions listed below are exact for Saturday night/Sunday
morning January 13/14. 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. This method 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.

These showers are expected to be active this week:

The Antihelion (ANT) radiant is now centered at 08:24 (126) +17. This area
of the sky lies in central Cancer near the dim star Theta Cancri. This
radiant is best placed near 0100 local standard time when it lies on the
meridian and is highest in the sky. Rates at this time should be near two
per hour as seen from the northern hemisphere and one per hour for observers
located south of the equator. With an entry velocity of 30 km/sec., the
average Antihelion meteor would be of medium-slow speed.

The Coma Berenicids (COM) peaked near December 20 with an average ZHR of
five. Rates have now fallen to less than one per hour no matter your
location. The current location of this radiant is 13:08 (197) +15. This area
of the sky is located in eastern Coma Berenices just two degrees south of
the fourth magnitude star Alpha Comae Berenices. These meteors are best seen
near 0600 local standard time when the radiant lies highest above the
horizon. At 65 km/sec. the Coma Berenicids will usually produce meteors of
swift velocity.

Sporadic rates have passed the late year plateau for observers located in
the northern hemisphere. One would expect to see perhaps fourteen random
meteors during the last hour before dawn from rural observing sites. During
the first dark hour after the end of evening twilight, perhaps four random
meteors can be seen per hour. Sporadic rates increase as the night
progresses so rates seen near midnight would be near nine per hour. Sporadic
rates seen from the southern hemisphere are near the first of two annual
maximums. One would expect to see approximately the same rates that are
visible from the northern hemisphere.

Antihelion (ANT) - 08:24 (126) +17
Northern Hemisphere - 2   Southern Hemisphere - 1

Coma Berenicids (COM)  13:08 (197) +15
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#X2006

Clear Skies!
Robert Lunsford
American Meteor Society