Meteor Activity Outlook for August 8-14, 2009

Meteor activity kicks into high gear in August
as seen from the northern hemisphere. The main reason for all this activity is
the Perseid shower that peaks on August 12. This shower is active most of the month
and remains above the level of the sporadic background for a week centered on
August 12. The sporadic activity is also increasing as seen from the northern
hemisphere and is now nearly double the rates from just three months ago. As seen
from south of the equator, meteor rates are still decent but falling rapidly. The
sporadic rates seen at the beginning of the month will be twice as much as
those seen during the last days of the month. The Perseid radiant does not
rise high into the sky as seen in the southern hemisphere so rates from this
shower are greatly reduced when compared to the northern hemisphere.

During this period the moon reaches its last quarter
phase on Thursday August 13th. This weekend the bright moon will be present most
of the night, significantly reducing the meteor activity seen. As the week progresses
the moon will exit the evening sky but will still cause interference during the prime
morning hours. The estimated total hourly rates for evening observers this week is
near four no matter your location. For morning observers the estimated total hourly
rates should be near twenty no matter your location 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. Rates are reduced this week
due to intense moonlight.

The radiant positions and rates listed below are exact
for Saturday night/Sunday morning August 8/9. 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 table below presents a summary of the expected activity this week. Rates and
positions are exact for Saturday night/Sunday morning August 8/9, but may be used
all week.

The full descriptions of each active meteor shower will continue next week when
the moon becomes less of a nuisance to observers.