(meteorobs) Meteor Activity Outlook for April 28-May 4, 2006

[Robert Lunsford]

With the arrival of May, observers in the tropical areas of the world are
enjoying good views of the Eta Aquarids during the morning hours. The
Antihelion radiant moves from eastern Libra, through northern Scorpius and
into southern Ophiuchus during May. These areas of the sky are south of the
celestial equator, favoring observers watching from south of the equator.
Northern observers still suffer with low sporadic rates, especially during
the evening hours. This situation will not improve until mid-July, when
sporadic rates dramatically rise for northern observers. The overall meteor
activity is much like April, possibly slightly better in the south and
slightly worse in the north. The most favorable time to view meteor activity
this month would be during the first week of the month, when the Eta
Aquarids are near maximum activity.

During this period the moon will enter the evening sky as a slender
crescent. It will sent by midnight during this entire period allowing the
more active morning hours to be free of interfering moonlight. The estimated
total hourly rates for evening observers this week is near two for observers
in the northern hemisphere and three for those south of the equator. For
morning observers the estimated total hourly rates should be near eleven for
those in the northern hemisphere and sixteen 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.

The radiant positions listed below are exact for Saturday night/Sunday
morning April 29/30. 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. 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 Antihelion (ANT) radiant is now centered at 15:28 (232) -19. This area 
of
the sky is located in eastern Libra, lying directly between the brilliant
planet Jupiter. and the orange first magnitude star Antares (Alpha Scorpii).
This radiant is best placed near 0200 local daylight time when it lies on
the meridian and is highest in the sky. Rates at this time should be near
two per hour for those north of the equator and three per hour south of the
equator. With an entry velocity of 30 km/sec., the average Anthelion meteor
would be of medium-slow speed.

The Eta Aquarids (ETA) are particles from Halley's Comet, which last passed
through the inner solar system in 1986. Even though this is now twenty years
ago, material is still encountered every year in late April and throughout
most of May. We pass closest to Halley's orbit on May 6. At that time Eta
Aquarid rates can reach 30 shower members per hour as seen from the northern
tropical areas southward. Current hourly rates would be 2-3 from the mid to
high latitudes of both hemispheres and five as seen from the tropical areas.
The radiant is located at 22:08 (332) -04. This area of the sky is located
in central Aquarius, four degrees south of the third magnitude star
Sadalmelik (Alpha Aquarii). The best time to view this activity is just
before the start of morning twilight, when the radiant lies highest in a
dark sky. With an entry velocity of 66 kilometers per second, a majority of
these meteors will appear to move swiftly.

The Sporadic rates for the Northern Hemisphere are now nearing their annual
minimum activity. One would expect to see perhaps six random meteors per
hour during the last hours before dawn from rural observing sites. During
the evening hours perhaps two random meteors can be seen per hour. Sporadic
rates seen from the southern hemisphere are now increasing toward a
secondary maximum in July. One would see approximately eight random meteors
per hour during the late morning hours and three per hour during the
evening.

Antihelion (ANT)  15:28 (232) -19
Northern Hemisphere 2 - Southern Hemisphere 3

Eta Aquarids (ETA)  22:07 (332) -04
Northern Hemisphere 3 - Southern Hemisphere 5

*For a detailed explanation on the different classes of meteor showers and
other astronomical terms, please visit:
http://www.amsmeteors.org/showers.html#X2006

Clear Skies!
Robert Lunsford
American Meteor Society