Meteor Activity Outlook for March 16-22, 2007

March provides some of the lowest meteor activity
of the year. This is especially true for northern observers. There are no major
showers active this month and only one minor shower that peaks this month (Gamma
Normids), and its existence is suspect. This suspected radiant is best seen from
the southern hemisphere. The only other radiant active this month (other than the
declining Delta Leonids) is the antihelion radiant, now situated in Virgo. On the
bright side, March is prime time for evening fireballs and many have been reported
during star parties and Messier marathons this month.

During this period the moon reaches its new
phase on Monday March 19. At this time the moon will be located near the sun and
will not interfere with meteor observing this week. The estimated total
hourly rates for evening observers this week is near two for those north of the
equator and three for observers south of the equator. For morning observers the
estimated total hourly rates should be near ten for northern observers and
fifteen for those south of the equator. 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 March 17/18. 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. Doing this 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 Antihelion (ANT) radiant is now centered at 12:40 (190) -05. This area
of the sky is centered in central Virgo, three degrees south of the famous third
magnitude double star Porrima (Gamma Virginis). This radiant is best placed near
0200 LDT when it lies on the meridian and is highest in the sky. Rates at this
time should be near two per hour no matter your location. With an entry velocity
of 30 km/sec., the average Antihelion meteor would be of medium-slow speed.

The Gamma Normids (GNO) are a bit suspect at this time. Not only is the
activity suspect but the radiant position is not positively known. The published
date of maximum activity is March 14 but newer data may show that it occurs a few
days later. The published radiant is currently located at 16:12 (243) -50. This
position lies in central Norma, two degrees west of the fourth magnitude star
Gamma Normae. Predicted ZHR’s are near four at maximum activity. Due to
the far southern declination of the radiant, this shower is not well seen north
of the northern equatorial regions. This area of the sky is best placed near
0600 LDT when it lies highest in the sky. At 56 km/sec. the Gamma Normids normally
produce meteors of swift angular velocities.

Sporadic rates are slowing decreasing for observers in the northern
hemisphere and slightly rising for those south of the equator. One would expect
to see perhaps eight random meteors during the last hour before dawn from rural
observing sites located in the northern hemisphere. 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. Late morning sporadic rates seen from the
southern hemisphere are now near a dozen per hour 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.