Meteor Activity Outlook for August 16-22, 2008

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. The 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 full
phase on Saturday August 16. At this time the moon will rise near evening twilight
and will remain in the sky all night long. As the week progresses the moon will
rise later in the evening giving a growing window of darkness just after evening
twilight. The more active morning hours will still suffer from the intense moonlight.
Good opportunities to view the weak evening showers such as the Kappa Cygnids and the August
Capricornids are possible later in the week. The estimated total hourly rates for evening observers
this week is near three for those located in the mid-northern hemisphere (45 N) and
two for those viewing from the mid-southern hemisphere (45 S). For morning observers
the estimated total hourly rates should be near twelve for those located in the
mid-northern hemisphere (45 N) and five 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. Rates are reduced this week due to
intense moonlight.

The radiant positions and rates listed below are exact
for Saturday night/Sunday morning August 16/17. 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 full descriptions of each active meteor shower will continue next week when
the moon becomes less of a nuisance to observers.

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