(meteorobs) Meteor Activity Outlook for February 28-March 6, 2009

[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 lies highest this time of year during the
evening hours.

During this period the moon reaches its first quarter phase on Wednesday
March 4th. At this time the moon lies ninety degrees east of the sun in the
and sets near midnight. During this entire period the more active morning
hours are free from lunar interference. The estimated total hourly rates for
evening observers this week is near two as seen from the northern hemisphere
and three for those situated south of the equator. For morning observers the
estimated total hourly rates should be near ten for those located in the
mid-northern hemisphere (45 N) and fourteen for those viewing from the
mid-southern hemisphere (45 S). Locations between these two extremes would
see activity between the listed figures. 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. Evening rates are slightly reduced due to lunar
interference.

The radiant positions and rates listed below are exact for Saturday
night/Sunday morning February 28/March 1. 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 weak Delta Leonids (DLE) reached maximum on Wednesday February 25th.
Visual rates are currently less than one per hour, no matter your location.
The radiant is now located at 11:28 (172) +15. This area of the sky lies in
eastern Leo between two fairly bright stars, Denebola (Beta Leonis) and
Theta Leonis. This radiant is best placed near 0100 local standard time 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. Do not
confuse these meteors with the overlapping Antihelion radiant, whose center
lies thirteen degrees to the south. To separate these meteors, the observer
must be facing in a direction that allows both radiants to be included
within your field of view.

The wide Antihelion (ANT) radiant is now centered at 11:32 (173) +02. This
area of the sky lies in southeastern Leo, five degrees west of the fourth
magnitude star Beta Virginis. This radiant is also best placed near 0100
LST. Due to the large size of this radiant, any meteor radiating from
southeastern Leo, western Virgo, or eastern Sextans 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 15:00
(225) -51. This area of the sky is located in southern Lupus, two degrees
northwest of the third magnitude star Zeta Lupi. with the maximum not
occurring until March 13th, current visual rates would still be less than
one shower member per hour, no matter your location. These meteors are best
seen between 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 throughout most of the northern hemisphere. An occasional shower
member may be seen from the northern tropics, shooting upwards from the
southern horizon. At 56 km/sec. the Gamma Normids will usually produce
meteors of swift velocity.

As seen from the mid-northern hemisphere (45N) one would expect to see
approximately nine Sporadic meteors per hour during the last hour before
dawn as seen from rural observing sites. Evening rates would be near two per
hour. As seen from the mid-southern hemisphere (45S), morning rates would be
near twelve 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. Evening rates are slightly reduced due
to lunar interference.

The table below presents a summary of the expected activity this week. Rates
and positions are exact for Saturday night/Sunday morning but may be used
all week.

Delta Leonids (DLE) - 11:28 (172) +15   Velocity - 23km/sec.
Hourly Rates - Northern Hemisphere - <1   Southern Hemisphere - <1

Antihelion (ANT) - 11:32 (173) +02   Velocity - 30km/sec.
Hourly Rates - Northern Hemisphere - 2   Southern Hemisphere - 2

Gamma Normids (GNO)  15:00 (225) -51   Velocity - 56km/sec.
Hourly Rates - 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#X2009

Clear Skies!
Robert Lunsford
American Meteor Society