Meteor Activity Outlook for October 12-18, 2007

Meteor activity in general increases in October
when compared to September. A major shower (the Orionids) is active most of the
month along with several minor showers. Both branches of the Taurids become more
active as the month progresses, providing slow, graceful meteors to the nighttime
scene. The Orionids are the big story of the month reaching maximum activity on
the 21st. This display can be seen equally well from both hemispheres which
definitely helps out in the sporadic-poor southern skies this time of year.

During this period the moon is a waxing crescent
and limited to the evening sky. Therefore it will not interfere with the prime
time morning observations. The estimated total hourly rates for evening observers
this week is near four 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 for those located in the
mid-northern hemisphere (45 N) and eight 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.

The radiant positions and rates listed below are exact
for Saturday night/Sunday morning October 13/14. 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:

Sirko Molau’s studies of video radiants has revealed activity in Ursa Minor
between October 10 and 16, peaking on the 12th. The position at maximum activity
is 16:32 (248) +82. This position lies in central Ursa Minor near the faint star
Epsilon Ursae Minoris. Visual activity is expected to be low, but detectable. The
radiant is best placed as soon as it becomes dark during the evening hours. At
35km/sec., the average Epsilon Ursae Minorid will appear as medium-slow.

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. Although
the radiants actually lie in Aries during October, they reach maximum
activity in November when they are situated in the constellation of Taurus.

The Northern Taurid (NTA) radiant is now centered at 02:12 (033) +16. This
position lies in western Aries, seven degrees south of the second magnitude star
Hamal (Alpha Arietis). The Southern Taurid (STA) radiant lies at 02:20 (035)
+11. This position lies in southwestern Aries, twelve degrees southeast of the
second magnitude star Hamal (Alpha Arietis). The two radiants are separated by
slightly over five degrees. Since they have 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.

The Orionids (ORI) are becoming more numerous from a radiant located at
06:04 (91) +15. This position lies in northeastern Orion, eight degrees north
of the orange first magnitude star Betelgeuse (Alpha Orionis). The radiant rises
near 2300 LDT and is best placed on the meridian near 0500. With maximum activity
predicted for October 21, current rates for all locations would be near two to three
per hour At 66km/sec., the average Orionid is swift.

The Epsilon Geminids (EGE) are now active from a radiant located at 06:32
(098) +27. This position lies in western Gemini, three degrees northwest of the
third magnitude star Epsilon Geminorum. Maximum activity is predicted to occur on
October 18 with an average ZHR of two. Current rates will be most likely less than
one per hour. Recent studies of video data
by Sirko Molau has indicated that this shower is more active earlier in the month
with a maximum occurring on October 14. Stronger rates occurring now would
indicate the earlier maximum is correct. At 70km/sec., the average Delta Aurigid
is swift.

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 fifteen 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 four random meteors can
be seen per hour. As seen from the mid-southern hemisphere (45 S) late morning rates
would now be near four per hour. During the first dark hour after the end of evening
twilight, perhaps one random meteor can be seen per hour.