Meteor Activity Outlook for October 25-31, 2008

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 observers located in the sporadic-poor southern hemisphere
this time of year.

During this period the moon reaches its new
phase on Tuesday October 28th. At this time the moon will be located near the sun
and will not be visible in the night sky. This weekend the waning crescent moon
will not interfere with meteor observing as it will be thin and will rise during
the late dark morning hours. The estimated total
hourly rates for evening observers this week is near eight for those located in
the mid-northern hemisphere (45 N) and five for those viewing from the mid-southern
hemisphere (45 S). For morning observers the estimated total hourly rates should
be near thirty for those located in the mid-northern hemisphere (45 N) and fifteen
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.

The radiant positions and rates listed below are exact
for Saturday night/Sunday morning October 25/26. 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. 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 center of the large Northern Taurid (NTA) radiant is now centered at
02:52 (043) +19. This position lies in central Aries, ten degrees southeast of
the second magnitude star Hamal (Alpha Arietis). The center of the large Southern
Taurid (STA) radiant lies at 02:52 (043) +13. This position also lies in
southern Aries, fifteen degrees southeast of the second magnitude star Hamal (Alpha
Arietis). 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 less difficult to
distinguish those meteors traveling east or west. These radiants are best placed
near the meridian at 0200 local daylight time (LDT). 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 Orionids (ORI) peaked on the morning of October 21st. Rates will now
dwindle until the shower is no longer detectable. The radiant is now located at
06:32 (98) +16. This position lies in southwestern Gemini, two degrees southwest
of the second magnitude star Alhena (Gamma Geminorum). The radiant rises near 2300 LDT
and is best placed on the meridian near 0500. At 66km/sec., the average Orionid is
swift.

Sirko Molau’s studies of video radiants has revealed activity in northern
Cancer between October 10 and November 4, peaking on the October 14th. The radiant
for the Iota Cancrids (ICA) lies at 09:16 (139) +29. This position lies in
northeastern Cancer, five degrees east of the fourth magnitude star Iota Cancri.
Visual activity is expected to be low, especially since we are now nearly two weeks
past the peak. The radiant rises near 0200 LDT and is best placed high in the east
during the last dark hour of the morning. At 67km/sec., the average Iota Cancrid
will appear move swiftly through the skies.

The Leo Minorids (LMI) are active from October 17-27 with maximum activity
occurring on October 23rd. ZHR’s are usually low but the radiant is far removed from
the Orionids so that any possible shower members should be easily
identified. This radiant is currently located at 10:56 (164) +37, which places it on
the Leo Minor/Ursa Major border, just north of the faint star 46 Leo Minoris. The
radiant is best placed just before dawn when it lies highest in a dark sky. This
shower is better situated for observers situated in the northern hemisphere where
the radiant rises far higher into the sky before the start of morning twilight.
At 62km/sec., the average Leo Minorid is swift.

As seen from the mid-northern hemisphere (45N) one would expect to see approximately
sixteen 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 five 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.

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.