Meteor Activity Outlook for November 16-22, 2007

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 but the sporadic rates are much lower than those seen in the northern
hemisphere.

During this period the moon reaches it first
quarter phase on Saturday November 17. At this time the moon will be located
ninety degrees east of the sun and will set near midnight local standard time.
During the latter portion of this period the waxing gibbous moon will start to
hamper observing as the window between moonset and the start of morning twilight
lessens. The estimated total hourly rates for evening observers
this week is near three for those located in the mid-northern hemisphere (45 N) and
one for observers from the mid-southern hemisphere (45 S). For morning observers
the estimated total hourly rates should be near twenty five for those located in the
mid-northern hemisphere (45 N) and ten for those viewing from the mid-southern
hemisphere (45 S). 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 due to moonlight.

The radiant positions and rates listed below are exact
for Saturday night/Sunday morning November 17/18. 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 Northern Taurid (NTA) radiant is now centered at 04:12 (063) +24. This
position lies in northern Taurus, five degrees east of the famous naked eye star
cluster known as the Pleiades or Seven Sisters. The Southern Taurid (STA)
radiant lies at 04:08 (062) +16. This position lies five degrees west of the
first magnitude orange star Aldebaran (Alpha Tauri). The two radiants are separated
by seven degrees. Since they have the 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. At 29 and 27 km/sec., the average Taurid meteor travels slowly through
the skies.

Sirko Molau’s study of video radiants has revealed a radiant located at 5:00 (075)
+30 active between November 15-20. This position lies in the extreme southeast
corner of Auriga, four degrees south of the third magnitude star Iota Aurigae.
This position is close to the radiant of the North Taurids so care must be taken
to differentiate between these radiants. These meteors are best seen near 0100
Local Standard Time (LST) when the radiant lies highest above the horizon in a
dark sky. Maximum activity occurs on the 17th. Rates are expected to be low but
further investigation of this radiant is needed. At 35 km/sec. the Iota Aurigids
produce meteors of average velocity.

Video data has also shown that activity from northern Orion begin appearing on
November 17 from a radiant located at 5:28 (082) +15. This position lies five
degrees north of third magnitude Lambda Orionis. Current rates would be low, most likely
less than one per hour. These meteors are best seen near 0200 Local Standard Time
(LST) when the radiant culminates on the meridian. Maximum activity occurs on the
28th. At 42 km/sec. the Lambda Orionids produce meteors of average velocity.

The Alpha Monocerotids (AMO) reach maximum activity on November 22 with
normally low rates of one or two shower members per hour. This shower has
produced outbursts in the past but none are expected for many years to come.
The radiant is located at 07:48 (117) +01. This position lies in
southeastern Canis Minor, five degrees southeast of the zero magnitude star
Procyon (Alpha Canis Minoris). These meteors are best seen near 0400 LST
when the radiant lies highest above the horizon in a dark sky. At 65 km/sec.
the Alpha Monocerotids produce mostly swift meteors.

The Leonids (LEO) are predicted to peak on November 18 from a radiant
located at 10:12 (153) +22. This position lies in western Leo, within the “Sickle”
and very close to the position of the third magnitude star Algeiba (Gamma Leonis).
The radiant is best placed during the last hour before dawn when it lies highest
in a dark sky. Rates at maximum are difficult to predict but they should range this year anywhere
from ten to thirty shower members per hour. 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 Leonid is swift with
a high percentage of trains.

Sporadic rates have reached maximum for observers in the northern
hemisphere and are now slowly rising for those located south of the equator. One
would expect to see approximately sixteen random meteors during the last hour before
dawn from rural observing sites in the mid-northern hemisphere (45 N). During the
first dark hour after the end of evening twilight, perhaps three random meteors can
be seen per hour. As seen from the mid-southern hemisphere (45 S) late morning rates
would now be near six per hour. During the first dark hour after the end of evening
twilight, perhaps one random meteor can be seen per hour. Moonlight interferes
with evening rates