(meteorobs) Meteor Activity Outlook for March 28-April 3, 2009

[Robert Lunsford]

Meteor activity picks up a bit during April as two major showers are active
during the month. The first of these, the Lyrids, are active from the 16th
through the 27th, with a pronounced maximum on the 22nd and 23rd. The Eta
Aquariids start appearing near the 27th and reach maximum activity during 
the
first week in May. Sporadic rates are low but steady as seen from the
mid-northern hemisphere (45 N). Sporadic rates seen from the mid-southern
hemisphere (45 S) rise this month toward a maximum in July.

During this period the moon reaches its first quarter phase on Thursday
April 2nd. At this time the moon lies ninety degrees east of the sun and
sets near 0100 local daylight time (LDT). This weekend the waxing crescent
moon will set during the evening hours allowing the more active morning
hours to remain free of interfering moonlight. The estimated total hourly
rates for evening observers this week is near three as seen from the
northern hemisphere and four 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.

The radiant positions and rates listed below are exact for Saturday
night/Sunday morning March 28/29. 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 13:24 (201) -09. This
area of the sky lies in central Virgo only two degrees north of the first
magnitude star Spica (Alpha Virginis). This radiant is also best placed near
0200 LDT. Due to the large size of this radiant, any meteor radiating from
eastern Corvus, western Libra, 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 30km/sec., the average Antihelion meteor
would be of medium-slow speed.

The video studies of Sirko Molau have revealed a weak radiant active in
Cygnus this time of year. The Zeta Cygnid (ZCY) radiant is currently located
at 19:48 (297) +36. This area of the sky is located in western Cygnus, three
degrees northwest of the fourth magnitude star Eta Cygni. Maximum activity
does not occur until April 10 so current rates are expected to be well less
than one per hour. These meteors are best seen during the last dark hour
before dawn, when the radiant lies highest above the horizon in a dark sky.
This shower is best seen from the northern hemisphere, where the radiant
lies high in the sky at dawn. At 41 km/sec. the Zeta Cygnids will usually
produce meteors of medium velocity.

As seen from the mid-northern hemisphere (45N) one would expect to see
approximately eight 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 three per hour
during the evening hours. Locations between these two extremes would see
activity between the listed figures.

The list 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.

Antihelion (ANT) - 13:24 (201) -09   Velocity - 30km/sec.
Hourly Rates - Northern Hemisphere - 2   Southern Hemisphere - 2

Zeta Cygnids (ZCY)13:24 (201) -09   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