(meteorobs) Meteor Activity Outlook for February 29-March 6, 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 last quarter phase on Friday
February 29th. At this time the moon will be located ninety degrees west of
the sun and will rise near midnight local standard time. The moon will
remain in the morning sky the remainder of the night but successful meteor
observations can be undertaken if you manage to keep the moon out of your
field of view. The estimated total hourly rates for evening observers this
week is near two no matter your location. For morning observers the
estimated total hourly rates should be near eight for those located in the
mid-northern hemisphere (45 N) and ten for those viewing from the
mid-southern hemisphere (45 S). 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. Morning rates are reduced due to the moonlight.

The radiant positions and rates listed below are exact for Saturday
night/Sunday morning March 1/2. 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 Delta Leonids (DLE) reached maximum activity on February 25. Rates are
now falling and will be less than one at this time. The radiant is located
at 11:32 (173) +14. This area of the sky lies in eastern Leo, four degrees
west of the second magnitude star Denebola (Beta 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 medium-slow speed.

The wide Antihelion (ANT) radiant is now centered at 11:36 (174) +01. This
area of the sky lies on the Leo-Virgo border, three degrees west of the
fourth magnitude star Beta Virginis. This radiant is best placed near 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 as seen from the northern hemisphere and one per hour for observers
located south of the equator. 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 15:08
(227) -50. This area of the sky is located in southeastern Lupus, three
degrees north of the third magnitude star Zeta Lupi. Current rates would be
less than one shower member per hour. 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 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.

Sporadic rates are now slowly falling no matter your location. One would
expect to see approximately six random meteors during the last hour before
dawn from rural observing sites in the northern hemisphere and nine from the
southern hemisphere. During the first dark hour after the end of evening
twilight, perhaps two random meteors can be seen per hour, no matter your
location. Moonlight reduces rates seen during the morning hours.

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

 Delta Leonid (DLE)  11:32 (173) +14 23   Velocity - 23km/sec.
Northern Hemisphere - <1   Southern Hemisphere - <1

Antihelion (ANT) - 11:36 (174) +01 30   Velocity - 30km/sec
Northern Hemisphere - 2   Southern Hemisphere - 1

Gamma Normids (GNO) Mar 13 15:08 (227) -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