(meteorobs) Meteor Activity Outlook for September 15-21, 2006

[Robert Lunsford]

Although there are no major showers active in September, meteor rates in the
northern hemisphere continue to be strong. Minor activity from the
constellations of Auriga, Perseus, and Taurus, as well as strong sporadic
rates, produce these impressive rates. Rates as seen from the southern
hemisphere have dropped off significantly since the July peak. Other than
weak sporadic rates, only the antihelion radiant produces any notable shower
activity in the southern skies.

This week the moon wanes from a half phase to a very slender crescent. With
each passing night the moon will rise later and will pose less of a problem
to observers. The estimated total hourly rates for evening observers this
week is near three for those north of the equator and one for those south of
the equator. For morning observers the estimated total hourly rates should
be near fourteen for those in the northern hemisphere and six for those
south of the equator. 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.
Morning rates are slightly reduced by moonlight.

The radiant positions listed below are exact for Saturday night/Sunday
morning September 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. 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.

These showers are active this week:

The large Antihelion (ANT) radiant is now centered at 00:28 (007) +03. This
area of the sky is centered in southern Pisces, six degrees southwest of the
fourth magnitude star Delta Piscium. This radiant is best placed near 0200
local daylight time (LDT) when it lies on the meridian and is highest in the
sky. Rates at this time should be near two per hour regardless of your
location. With an entry velocity of 30 km/sec., the average antihelion
meteor would be of medium-slow speed.

The Delta Aurigids (DAU) reach a weak peak on October 4. Current rates would
most certainly be less than one per hour. The radiant is located at 04:32
(68) +48. This portion of the sky lies in eastern Perseus, eight degrees
west of the brilliant zero magnitude star Capella (Alpha Aurigae). Due to
the extreme northern declination of this radiant, this shower is only
visible from the southern tropics northward. The radiant is best placed near
0500 LDT, when it lies on the meridian. At 64km/sec.,the average Delta
Aurigid is swift.

Sporadic rates continue to climb slowly for observers located in the
northern hemisphere. One would expect to see perhaps twelve random meteors
during the last hour before dawn from rural observing sites. During the
first dark hour after the end of evening twilight, perhaps three random
meteors can be seen per hour. Sporadic rates increase as the night
progresses so rates seen near midnight would be near seven per hour.
Sporadic rates seen from the southern hemisphere have fallen drastically
since the July maximum. One would see approximately four random meteors per
hour during the last hour before dawn and one per hour during the first dark
hour after the end of evening twilight. Rates near midnight would be near
two per hour. Morning rates are slightly reduced by moonlight.

Antihelion (ANT) - 00:28 (007) +03
Northern Hemisphere - 2  Southern Hemisphere - 2

Delta Aurigids (DAU) 04:32 (068) +48
Northern Hemisphere - >1  Southern Hemisphere - 0

*For a detailed explanation on the different classes of meteor showers and
other astronomical terms, please visit:
http://www.amsmeteors.org/showers.html#X2006

Clear Skies!
Robert Lunsford
American Meteor Society