Meteor Activity Outlook for September 27-October 3, 2008

Meteor activity in general increases in October
when compared to September. A major shower (the Orionids) is active most of the
month along with several minor showers. Both branches of the Taurids become more
active as the month progresses, providing slow, graceful meteors to the nighttime
scene. The Orionids are the big story of the month reaching maximum activity
on the 21st. This display can be seen equally well from both hemispheres
which definitely helps out observers located in the sporadic-poor southern hemisphere
this time of year.

During this period the moon reaches its new
phase on Monday September 29th. At this time the moon will be located near the
sun and will not be visible at night. Later in the period the waxing crescent moon
will enter the evening sky but set soon after the end of evening twilight. It will
not interfere with meteor observing no matter the hour. The estimated total
hourly rates for evening observers this week is near six for those located in
the mid-northern hemisphere (45 N) and three for those viewing from the mid-southern
hemisphere (45 S). For morning observers the estimated total hourly rates should
be near twenty for those located in the mid-northern hemisphere (45 N) and ten 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 September 27/28. 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 center of the large Northern Taurid (NTA) radiant is now centered at
01:24 (021) +12. This position lies in eastern Pisces, three degrees southwest of
the fourth magnitude star Eta Piscium. The center of the large Southern Taurid
(STA) radiant lies at 01:36 (024) +07. This position also lies in eastern Pisces,
three degrees southwest of the fourth magnitude star Eta Piscium. The two
radiants are separated by slightly over five degrees. Since they have nearly
the same right ascension (celestial longitude), it is difficult to
distinguish meteors that move north or south out of the radiants. It is less
difficult to distinguish those meteors traveling east or west. These radiants are
best placed near the meridian at 0200. At 29 and 27 km/sec., the average Taurid
meteor travels slowly through the skies.

The Delta Aurigids (DAU) are present in the morning skies in the second half
of September and early October. Maximum activity occurs on October 3rd with an
average ZHR of two. Current rates will be most likely near one per hour as seen
from the northern hemisphere and less than one as seen from the south of the
equator. The radiant is currently located 05:24 (081) +49. This position lies in
northwestern Auriga, three degrees north of the zero magnitude star Capella
(Alpha Aurigae). At 64km/sec., the average Delta Aurigid is swift.

Sirko Molau’s study of video radiants has shown an active radiant located in Orion
during this period. The September Alpha Orionids (AOR) peak on September
27th with a radiant located near 05:24 (081) +07. The area of the sky is located
in northwestern Orion near the bright star Bellatrix (Gamma Orionis). Activity
is more than a ZHR of one between September 24th and the 30th. This radiant was
one of the strongest new showers detected in the video survey. Meteors from this
radiant are not visible during the evening hours as Orion lies beneath the horizon
during this time. The radiant gains altitude during the morning hours and is most
favorably located near 0600 LDT when it lies highest above the horizon. Due to its
location near the celestial equator, activity is visible nearly everywhere. Tropical
locations are favored as the radiant passes overhead. Hourly rates this week would
be near one no matter your location. With an entry velocity of 59 km/sec.,
most members of the September Alpha Orionids would possess a swift velocity.

During 2005 and 2006 a shower of bright meteors has occurred on October 5th and 6th,
radiating from near the Draco/Camelopardalis border. The 2007 display was missed
due to moonlight and clouds. The October Camelopardalids (OCT) peak for only
a few hours but shower members are bright and should be easy to observe. The 2008
display is predicted to occur near 14 UT on October 5th, which corresponds to 0700
PST. It is daylight at this time from the USA’s west coast but observers along the
Pacific coast of Canada and Alaska can view at this time. The last hour before dawn
may provide some activity as seen from the western USA and Canada. The estimated
position of the radiant on the 5th is 10:48 (162) +79. The nearest easy star to
identify the radiant is 4th magnitude SAO1551. Polaris (Alpha Ursae Minoris) lies
12 degrees to the north. This area of the sky is circumpolar from nearly the entire
northern hemisphere. The radiant lies highest above the horizon in a dark sky at
both dusk and at dawn. Due to this unusual situation this shower would be totally
invisible from the southern hemisphere. With an entry velocity of 47 miles per
second most members of the October Camelopardalids would be of medium-swift
velocity. Shower members should be seen from October 1-10, but at very low numbers
away from the peak hour on the 5th.

As seen from the mid-northern hemisphere (45N) one would expect to see approximately
fifteen Sporadic meteors per hour during the last hour before dawn as seen from
rural observing sites. Evening rates would be near four per hour. As seen from the
mid-southern hemisphere (45S), morning rates would be near four per hour as seen
from rural observing sites and one per hour during the evening hours. Locations
between these two extremes would see activity between the listed figures.

The table 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.