(meteorobs) Meteor Activity Outlook for January 26-February 1, 2007

Robert Lunsford lunro.imo.usa at cox.net
Sun Jan 28 21:32:52 EST 2007


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 waxes from half illumination to nearly full. With each
passing night the window of opportunity for dark skies between midnight and
dawn grows progressively smaller. 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 27/28. 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 09:24 (141) +14. This area
of the sky lies in western Leo, ten degrees north of the first magnitude
star Regulus (Alpha Leonis). 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.

Sporadic rates have passed the late year plateau for observers located in
the northern hemisphere. One would expect to see perhaps twelve random
meteors during the last hour before dawn from rural observing sites. During
the first dark hour after the end of evening twilight, perhaps two random
meteors can be seen per hour. Sporadic rates increase as the night
progresses so rates seen near midnight would be near five 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 three random meteors can be seen
per hour, increasing to six by midnight.

Antihelion (ANT) - 09:24 (141) +14
Northern Hemisphere - 2   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



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