(meteorobs) Meteor Activity Outlook for March 7-13, 2008

[Robert Lunsford]

March is the slowest month for meteor activity. No major annual showers are
active and only two very weak minor showers produce activity this month. The
sporadic rates continue a slow decline as seen from the mid-northern
latitudes and mid-southern rates reach a fist half minimum. There is not
much to look forward to this month expect for the evening fireballs that
seem to peak this time of year from the northern hemisphere. This could be
due to the fact the antapex lies highest this time of year during the
evening hours.

During this period the moon reaches its new phase on Friday March 7th. At
this time the moon will be located near the sun and will be invisible at
night. Early next week the moon will enter the evening sky as a waxing
crescent. The moon will have set by the time the more active morning hours
arrive. As seen from the mid-northern hemisphere (45 N) the estimated total
hourly rates during the evening observers would be two. For morning
observers the estimated total hourly rates should be near eight. For those
located in the mid-southern hemisphere (45 S) morning rates would be near
fourteen and evening rates near three. 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 and rates listed below are exact for Saturday
night/Sunday morning March 8/9. 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. Viewing there 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 following showers are expected to be active this week:

The wide Antihelion (ANT) radiant is now centered at 12:00 (180) -01. This
area of the sky lies in western Virgo, five degrees west of the fourth
magnitude star Eta Virginis. This radiant is best placed near 0200 local
daylight saving time (0100 local standard time) when it lies on the meridian
and is highest in the sky. Actually any meteor from western Virgo, northern
Crater, or southeastern Leo could be a candidate for this shower. 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 active from a radiant located at 15:32
(233) -50. This area of the sky is located in western Norma, four degrees
northeast of the third magnitude star Zeta Lupi. This shower peaks on the
13th so rates should be near one over the weekend and slightly elevated near
maximum. These meteors are best seen between 0500 and 0600 local daylight
saving time (0400 and 0500 local standard time), when the radiant lies
highest above the horizon. This shower is best seen from the southern
hemisphere, where the radiant lies high in the sky at dawn. Meteors from
this shower are not visible north of 40 degrees north latitude and also
poorly seen in the most of the northern hemisphere. An occasional member may
be seen from the northern tropics. At 56 km/sec. the Gamma Normids will
usually produce meteors of swift velocity.

As seen from the mid-northern hemisphere (45N) the Sporadic rates are still
slowly falling. One would expect to see approximately eight random meteors
during the last hour before dawn from rural observing sites and two per hour
during the evening hours. As seen from the mid-southern hemisphere (45S)
morning rates would be near 11 per hour as seen from rural observing sites
and three per hour during the evening hours.

The table below presents a condensed version of the expected activity this
week. Rates and positions are exact for Saturday night/Sunday morning.

Antihelion (ANT) - 12:00 (180) -01   Velocity - 30km/sec.
Northern Hemisphere - 2   Southern  Hemisphere - 2

Gamma Normids  Mar 13 15:32 (233) -50   Velocity - 56km/sec.
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#X2008

Clear Skies!
Robert Lunsford
American Meteor Society