Meteor Activity Outlook for November 15-21, 2008

As seen from the northern hemisphere, meteor
rates continue to be strong in November. While no major showers are active this
month, the two Taurid radiants plus the Leonids keep the skies active. The
addition of strong sporadic rates make November one of the better months to view
meteor activity from north of the equator. Skies are fairly quiet as seen from
the southern hemisphere this month. Activity from the three showers mentioned
above may be seen from south of the equator, but the sporadic rates are much
lower than those seen in the northern hemisphere.

During this period the moon reaches its last
quarter phase on Wednesday November 19th. At this time the moon will rise near
midnight local standard time (LST) and will remain in the sky the rest of the morning.
At this time successful meteor observations are possible if your sky is transparent
and you keep the bothersome moonlight out of your field of view. This weekend the
bright waning gibbous moon will severely hamper any attempts at observing. The
estimated total hourly rates for evening observers this week is near five for
those located in the mid-northern hemisphere (45 N) and two for those viewing from
the mid-southern hemisphere (45 S). For morning observers the estimated total
hourly rates should be near thirteen for those located in the mid-northern hemisphere
(45 N) and nine 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. Morning rates are reduced during this period due to moonlight.

The radiant positions and rates listed below are exact
for Saturday night/Sunday morning November 15/16. 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:

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 center of the large Northern Taurid (NTA) radiant is now centered at
04:08 (062) +23. This position lies in western Taurus some four degrees east of
the famous naked eye open star cluster known as the Pleiades or the Seven Sisters.
The center of the large Southern Taurid (STA) radiant lies at 04:04 (061)
+16. This position also lies in western Taurus, eight degrees west of the orange
first magnitude star Aldebaran (Alpha Tauri). The two radiants are separated by
approximately seven 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 less difficult to distinguish those meteors traveling east
or west. These radiants are best placed near the meridian at 0100 LST. At 29 and
27 km/sec., the average Taurid meteor travels slowly through the skies.

Sirko Molau’s new studies of video radiants has revealed that the Northern Taurid’s
reach two plateaus of activity with the first occurring on October 20th. The
moon subdued this activity so it was most likely not noticed. The secondary peak is
predicted to occur near November 13th and will be severely hampered by a bright
moon. The same study has revealed that the Southern Taurids may have peaked near
October 11 and that the activity for this shower will remain fairly constant through
the first week of November. After that rates will dwindle until these meteors disappear
near the end of November.

The Leonids (LEO) are now producing bright meteors from a radiant located at
10:00 (150) +23. This position lies in western Leo, three degrees west of the
third magnitude star Zeta Leonis. Maximum activity is predicted to occur on November
19 so current rates would most likely be near two per hour. There are several
predictions of short outbursts on the 17th and 18th so it is advisable to view the
Leonids during the entire period from the 17th through the 19th despite the moonlight.
Recent studies of video data by Sirko Molau has indicated that the Leonids are active
longer than expected, with ZHR’s of at least one through November 28. At 70km/sec.,
the average Leo is swift with a high percentage of trains. The radiant is most
favorably located during the last dark hour before the onset of morning twilight.

As seen from the mid-northern hemisphere (45N) one would expect to see approximately
eight 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 three 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. Morning
rates are reduced during this period due to moonlight.

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.