Meteor Activity Outlook for September 13-19, 2008

September offers longer nights and cooler
temperatures in the northern hemisphere. In the sky, no major showers are visible
from either hemisphere but the northern hemisphere enjoys the advantage of higher
sporadic rates. The two recognized minor showers active in early September have
high northern declinations (celestial latitude) therefore are much better suited
to be viewed from locations north of the equator. Toward the end of the month the
antihelion radiant becomes entangled with the two Taurid radiants and it is
impossible to separate them. Therefore the antihelion radiant will be excluded
from the list from the last week of September until the end of the Taurid activity
period late in November. Observers in the southern hemisphere suffer from some of
their lowest rates of the year this month. The Taurid radiants are not too badly
placed so observers south of the equator can expect to see a little of this
activity toward the end of the month.

During this period the moon reaches its full
phase on Monday September 15. 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.
The estimated total hourly rates for evening observers this week is near two for
those located in the mid-northern hemisphere (45 N) and one for those viewing from
the mid-southern hemisphere (45 S). For morning observers the estimated total hourly
rates should be near eight 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 September 13/14. 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.