(meteorobs) Meteor Activity Outlook for January 19-25, 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 reaches its new phase on Friday January 19th. At this
time it lies near the sun and is not visible at night. As the week
progresses the waxing crescent moon will enter the evening sky but will set
long before the more productive morning hours arrive. The estimated total
hourly rates for evening observers this week is near three for those viewing
from the northern hemisphere and four for those located south of the
equator. For morning observers the estimated total hourly rates should be
near thirteen for observers north of the equator and fifteen for those
observers viewing 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.

The radiant positions listed below are exact for Saturday night/Sunday
morning January 20/21. 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 08:52 (133) +16. This area
of the sky lies in eastern Cancer, two degrees southeast of the fourth
magnitude star Delta 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 three per hour as seen from the northern
hemisphere and two 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 13:28 (202) +13. This area
of the sky is located in northern Virgo, five degrees northeast of the third
magnitude star Vindemiatrix (Epsilon Virginis). These meteors are best seen
near 0500 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 thirteen random
meteors during the last hour before dawn from rural observing sites. During
the first dark hour after the end of evening twilight, perhaps three random
meteors can be seen per hour. Sporadic rates increase as the night
progresses so rates seen near midnight would be near eight per hour.
Sporadic rates seen from the southern hemisphere are near the first of two
annual maximums. One would expect to see perhaps fifteen 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.

Antihelion (ANT) - 08:52 (133) +16
Northern Hemisphere - 3   Southern Hemisphere - 2

Coma Berenicids (COM)  13:28 (202) +13
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