(meteorobs) Meteor Activity Outlook for March 6-12, 2010

[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 first 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 radiant lies highest above the horizon this time of 
year during the evening hours.

During this period the moon reaches its last quarter phase on Sunday March 7th. At this time the moon lies ninety degrees west of 
the sun and rises near midnight local standard time (LST). The moon will be a nuisance this weekend, but as the week progresses, its 
impact lessens. The estimated total hourly rates for evening observers this week is near two for northern observers and three for 
those viewing from south of the equator. For morning observers the estimated total hourly rates should be near seven from the 
northern hemisphere and nine as seen from the southern hemisphere. 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. Morning rates are 
reduced due to moonlight.

The radiant positions and rates listed below are exact for Saturday night/Sunday morning March 6/7. 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 11:56 (179) -01. This area of the sky lies in western Virgo, three degrees 
southeast of the fourth magnitude star Beta Virginis. This radiant is best placed near 0100 local standard time (LST) when it lies 
on the meridian and is located highest in the sky. Due to the large size of this radiant, any meteor radiating from eastern Leo, 
Sextans, Crater, or Virgo 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) is a weak shower best seen from the southern hemisphere. This shower is only visible south of forty degrees 
north latitude. The further one is located south (down to 50S) the better the radiant is situated in the sky. Expected rates from 
the southern hemisphere is only one per hour, even with the radiant located high in the sky. The current radiant position lies at 
16:12 (243) -52. This position lies in central Norma, two degrees southwest of the fourth magnitude star Gamma Normae. The radiant 
is best placed during the last dark hour before dawn, when it lies highest above the horizon in a dark sky. At 56km/sec. the Gamma 
Normids would produce mostly swift meteors.

As seen from the mid-northern hemisphere (45N) one would expect to see approximately five sporadic meteors per hour during the last 
hour before dawn as seen from rural observing sites. Evening rates would be near one per hour. As seen from the mid-southern 
hemisphere (45S), morning rates would be near six per hour as seen from rural observing sites and two per hour during the evening 
hours. Locations between these two extremes would see activity between the listed figures. Morning rates are reduced due to 
moonlight.

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)) - 11:56 (179) -01   Velocity - 30km/sec.
Northern Hemisphere - 2 per hr. Southern Hemisphere - 2 per hr.

Gamma Normids (GNO) - 16:12 (243) -52    Velocity - 56km/sec.
Northern Hemisphere - <1 per hr. Southern Hemisphere - 1 per hr.

*For a detailed explanation on the different classes of meteor showers and other astronomical terms, please visit: 
http://www.amsmeteors.org/showers.html#X2010

Clear Skies!
Robert Lunsford
American Meteor Society