(meteorobs) Meteor Activity Outlook for September 1-7, 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 will reach its full phase on Thursday September 7th. This
weekend the waxing gibbous moon will set during the early morning hours
allowing a small window of dark sky viewing between moonset and dawn. As the
week progresses this window of opportunity shrinks until it is gone by
Wednesday the 6th. The estimated total hourly rates for evening observers
this week is near two 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 twenty 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.
Evening rates are reduced by the intense moonlight.

The radiant positions listed below are exact for Saturday night/Sunday
morning September 2/3. 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 23:32 (353) -01. This
area of the sky is centered in western Pisces, two degrees southeast of the
faint star Kappa 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 September Perseids (SPE) reach a ZHR of one on September 5 and peak four
days later. The bright moon ruins the 2006 display of these meteors. Under
better conditions an observer in the northern hemisphere would see 3-4
shower members per hour on September 9. The radiant is located at 03:32 (53)
+46. This portion of the sky lies in central Perseus, four degrees south of
the second magnitude star Mirfak (Alpha Persei). Like the Alpha Aurigids
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 September Perseid is swift.

The Alpha Aurigids (AUR) peak on the morning of September 1 with an average
ZHR of ten. The actual rates fluctuate greatly from one year to the next.
While nothing out of the ordinary is expected from this shower in 2006, 2007
is viewed with anticipation as a possible outburst is predicted. While the
moon is favorable this year, it is not in 2007 as it will be only four days
past its full phase. The radiant is located at 05:44 (86) +42, which places
it in central Auriga, five degrees southeast of the brilliant zero magnitude
yellow star Capella (Alpha Aurigae). Rates fall off rapidly after the date
of maximum activity, rarely exceeding one shower member per hour by the 3rd.
Due to the extreme northern declination, this shower is only visible from
the southern tropics northward. The radiant is best placed just before the
start of morning twilight, when it lies highest in a dark sky. The radiant
actually culminates after sunrise. At 66km/sec., the average Alpha Aurigid
is swift.

Sporadic rates continue to climb slowly for observers located in the
northern hemisphere. One would expect to see perhaps fourteen random meteors
during the last hour before dawn from rural observing sites. During the
first dark hour after the end of evening twilight, perhaps two random
meteors can be seen per hour. Sporadic rates increase as the night
progresses so rates seen near midnight would be near six 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. Evening rates are reduced by the intense moonlight.

Antihelion (ANT) - 23:32 (353) -01
Northern Hemisphere  2  -  Southern Hemisphere  2

September Perseids (SPE) 03:32 (53) +46
Northern Hemisphere  >1  -  Southern Hemisphere  0

Alpha Aurigids (AUR)  05:44 (86) +42
Northern Hemisphere  1 -  Southern Hemisphere  <1

*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