Meteor Activity Outlook for March 9-15, 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 last quarter
phase on Monday March 12. At this time the moon will rise near 0100 local daylight
time and will hamper observing the remainder of the morning. 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 seven for northern observers and
nine 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. Rates are reduced
during the morning hours due to moonlight.

The radiant positions listed below are exact for Saturday
night/Sunday morning March 10/11. 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 Delta Leonids (DLE) are now near the end of their active period for 2007.
Rates seen from anywhere would now be less than one per hour from a radiant now
centered at 12:04 (181) +12. This area of the sky is centered in northwestern
Virgo, four degrees southeast of the second magnitude star Denebola (Beta Leonis).
This radiant is best placed near 0200 Local Daylight Time (LDT) when it lies on
the meridian and is highest in the sky. With an entry velocity of 23 km/sec., the
average Delta Leonid meteor would be of slow speed.

The Antihelion (ANT) radiant is now centered at 12:12 (183) -02. This area
of the sky is centered in western Virgo, two degrees west of the fourth magnitude
star Eta 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 15:45 (236) -50. This
position lies in a remote area of western Norma, eight degrees northeast of the
third magnitude star Iota Lupi. Predicted ZHR’s are near four at maximum activity.
Actual rates as seen from the southern hemisphere would be 1-2 per hour. 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 no matter your location. One
would expect to see perhaps five 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 four per hour. Sporadic rates seen from the southern
hemisphere are also falling toward a mid-month low. One would expect to see
perhaps six 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 five by midnight.
Morning rates are reduced due to moonlight.