Meteor Activity Outlook for October 5-11, 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 reaches its new
phase on Thursday October 11. At this time the moon is located close to the sun
and is invisible during the nighttime hours. This weekend the waning crescent
moon is a small nuisance and less of a problem as the week progresses. The
estimated total hourly rates for evening observers this week is near four for
those located north of the equator and two for observers south of the equator.
For morning observers the estimated total hourly rates should be near fifteen for
those located in the northern hemisphere and seven for those viewing from 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 slightly reduced due to
moonlight during this period.

The radiant positions and rates listed below are exact
for Saturday night/Sunday morning October 6/7. 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
(very close to the current position) 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.

The Draconids (GIA) are predicted to peak on October 9 near 0430 Universal Time.
This corresponds to the evening hours of October 8 for those located in the American
longitudes. The radiant is located at 17:28 (262) +54, which places it in southern
Draco, two degrees northwest of the third magnitude star Rastaban (Beta Draconis).
This star is one of the four that form the prominent head of Draco, also known as
the “Lozenge”. Expected rates are always a guess but usually quite low. Due to the
extreme northern declination, this shower is only visible from the southern tropics
northward. The radiant is best placed just as it becomes dark during the evening
hours. At 20km/sec., the average Draconid is extremely 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 01:52 (028) +14. This
position lies in western Aries, five degrees south of the fourth magnitude star
Mesarthim (Epsilon Arietis). The Southern Taurid (STA) radiant lies
at 02:00 (030) +08. This position lies in southeastern Pisces, six degrees
north of the fourth magnitude star Alrischa. 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 slightly 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 just beginning to appear from a radiant located at
05:44 (86) +14. This position lies in extreme eastern Taurus, five degrees northwest
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 one or two
per hour At 64km/sec., the average Orionid is swift.

The Delta Aurigids (DAU) are present in the morning skies in the second
half of September and early October. Maximum activity occurs on October 4 with an
average ZHR of two. Current rates will be most likely less than one per hour. The
radiant is located 06:00 (090) +49. This position lies in northern Auriga, four
degrees north of the second magnitude star Menkalinan (Beta Aurigae). Note
that in my last meteor outlook the position of this shower was given for the 25th
of September, not the 30th. The correct position for the 30th is six degrees further
east at 05:32 (083) +49. At 64km/sec., the average Delta Aurigid is swift.

Sporadic rates have nearly 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 twelve random meteors during the last hour before
dawn from rural observing sites in the northern hemisphere. During the first dark hour after the end of evening
twilight, perhaps four random meteors can be seen per hour. As seen from the
southern hemisphere late morning rates would now be near four per hour. During
the first dark hour after the end of evening twilight, perhaps two random meteors
can be seen per hour. Morning rates are slightly reduced due to moonlight during
this period.