Meteor Activity Outlook for April 10-16, 2010

During this period the moon reaches its new phase on Wednesday
April 14th. At this time the moon lies near the sun and cannot be seen at night. This weekend the
waning crescent moon will not cause any interference to meteor observers. The estimated total
hourly rates for evening observers this week is near three for northern observers and four for those viewing
from south of the equator. For morning observers the estimated total hourly rates should be near
ten from the northern hemisphere and sixteen 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.

The radiant positions and rates listed below are exact
for Saturday night/Sunday morning April 10/11. 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 14:16 (214) -13. This area of the sky
lies on the Virgo/Libra border, ten degrees west of the second magnitude star Zubenelgenubi (Alpha
Librae). This radiant is best placed near 0200 local daylight time (LDT) 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 Hydra, Libra, or Virgo could be a candidate for this shower. Rates at this
time should be near one per hour as seen from the northern hemisphere and two per hour as seen from
south of the equator. With an entry velocity of 30 km/sec., the average Antihelion meteor would be
of medium-slow speed.

The team of Sirko Molau and Juergen Rendtel have discovered a weak radiant active at this time in
the constellation of Cygnus. Video data shows that the Zeta Cygnids (ZCY) are active from
March 27th through April 18th. Maximum activity occurred on the morning of April 6th. The radiant
is currently located at 20:08 (302) +42. This position lies in central Cygnus, four degrees northwest of
the second magnitude star Sadr (Gamma Cygni). The radiant is best placed during the last dark hour
before dawn, when it lies highest above the horizon in a dark sky. At 44km/sec. the Zeta Cygnids
would produce meteors of medium velocity. Expected rates are near one per hour during the last
dark hour before dawn. Due to the northerly declination of the radiant, these meteors are not well
seen from south of the equator.

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