(meteorobs) Meteor Activity Outlook for November 10-16, 2006

[Robert Lunsford]

Meteor rates continue to be strong as seen from the northern hemisphere. The
antihelion radiant has merged with the two Taurid radiants producing slow
meteors that are visible during the evening and early morning hours. Swift
meteors from the Leonid radiant can be seen during the morning hours for two
weeks centered at mid-month. Strong sporadic rates continue during the
morning hours as long as the moon is below the horizon. From the southern
hemisphere, sporadic rates are increasing in strength toward a peak in
January. Meteors from the Leonid and Taurid radiants also help to fill the
southern skies with more activity. A new moon during the peak of the Leonid
shower will help provide observers with dark skies.

This week the moon reaches its last quarter phase on Sunday November 12. At
this time the moon will rise near midnight local standard time (LST) and
will hinder observing during the busy morning hours. This condition can be
overcome by facing away from the moon so that its glare does not ruin your
dark adapted eyes. The estimated total hourly rates for evening observers
this week is near five for those north of the equator and two for observers
south of the equator. For morning observers the estimated total hourly rates
should be near twenty for northern observers and ten 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
reduced due to moonlight.

The radiant positions listed below are exact for Saturday night/Sunday
morning November 11/12. 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. Doing this 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.

These showers are expected to be active this week:

Sirko Molau's study of video radiants has revealed activity during the
period November 8-15, from an area near where the borders of Pisces, Aries,
and Triangulum meet. Maximum occurs on November 9 with the radiant located
at 01:38 (025) +27. This position lies in northeastern Pisces, four degrees
southwest of the third magnitude star Alpha Triangulum. This radiant is best
placed on the meridian near 2200 (10:00pm) LST. It appears that six percent
of the total activity for the night is related to this radiant. At only
20km/sec., the average meteor from this radiant would be slow moving.

At this time of year debris from comet 2P/Encke produces a double radiant
very close to the position of the antihelion radiant. From now through the
end of November, it is impossible to resolve the antihelion meteors from
those produced by comet 2P/Encke. Therefore we suggest that observers simply
classify meteors from this area as either north or south Taurids.

The Northern Taurid (NTA) radiant is now centered at 03:52 (058) +22. This
position lies in western Taurus, just two degrees southeast of the Pleiades
star cluster. The Southern Taurid (STA) radiant lies at 03:52 (058) +15.
This position lies in western Taurus, seven degrees southeast of the
Pleiades star cluster. The two radiants are separated by slightly over five
degrees. Since they have the same right ascension (celestial longitude), it
is difficult to distinguish meteors that move north or south out of the
radiants. It is slightly less difficult to distinguish those meteors
traveling east or west.

These radiants are above the horizon most of the night and are best placed
near midnight LST, when they lie on the meridian and are located highest in
the sky. Rates at this time should be near two per hour for the southern
radiant and three per hour for the northern radiant, regardless of your
location. With an entry velocity near 30 km/sec., the average Taurid meteor
would be of medium-slow speed.

The Leonids (LEO) reach a ZHR of one on the 10th and rates slowly rise as
the week progresses. The radiant is located at 09:52 (148) +24. This
position lies in northwestern Leo, just east of the third magnitude star
Epsilon Leonis. The radiant rises near 2300 (11:00pm) LST and is best placed
in a dark sky just before the onset of morning twilight. At 71km/sec., the
average Leonid is swift.

Sporadic rates have reached the late year plateau 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 four random
meteors can be seen per hour. Sporadic rates increase as the night
progresses so rates seen near midnight would be near eight per hour.
Sporadic rates seen from the southern hemisphere have passed their annual
minimum and are rising again. One would expect to see approximately five
random meteors per hour during the last hour before dawn and two per hour
during the first dark hour after the end of evening twilight. Rates near
midnight would be near four per hour. Sporadic rates seen during the morning
hours are reduced this week due to moonlight.

Phi Piscids (PPI)  01:38 (025) +27
Northern Hemisphere - 1   Southern Hemisphere - >1

Northern Taurid (NTA) 03:04 (046) +20
Northern Hemisphere - 3   Southern Hemisphere - 3

Southern Taurid (STA)  03:04 (046) +14
Northern Hemisphere - 2   Southern Hemisphere - 2

Leonids (LEO)  09:52 (148) +24
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