Meteor Activity Outlook for October 24-30, 2009

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 22nd. 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 first
quarter phase on Monday October 26th. On that date the moon lies ninety degrees
east of the sun and sets near 0100 local daylight time (LDT), depending on your
location. As the week progresses the waxing gibbous moon sets later in the morning,
lessening the window of opportunity to view meteor activity in a dark sky. The
estimated total hourly rates for evening observers this week is near five as seen
from the northern hemisphere and two from the southern hemisphere. For morning
observers the estimated total hourly rates should be near twenty five from the
northern hemisphere and fifteen as seen from the southern hemisphere. 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 by moonlight.

The radiant positions and rates listed below are exact
for Saturday night/Sunday morning October 24/25. 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.

A new radiant has been discovered in Ursa Minor which is active during this
period. The October Ursa Minorids (OUI) are active from October 16-28,
with maximum occurring on the 24th. The current radiant position lies at 18:09
(272) +74. This position lies in eastern Draco near the faint star Chi Draconis.
The radiant is best placed just as soon as it becomes dark, when it lies highest
in a dark sky. Meteors from the October Ursa Minorids strike the atmosphere at
28km/sec., which would produce meteors of slow velocity. Expected rates would be
less than one per hour, as seen from the northern hemisphere. Activity from this
shower is not visible in the southern hemisphere due to the high northerly location
of the radiant.

The Northern Taurids (NTA) are active from a large radiant centered at
02:52 (043) +20, which lies in central Aries, five degrees west of the fourth
magnitude star Delta Arietis. The radiant is best placed near 0200 LDT, when it
lies highest above the horizon. Meteors from the Northern Taurids strike the
atmosphere at 29km/sec., which would produce meteors of slow velocity. Expected
rates would be near one per hour, no matter your location.

The center of the large Southern Taurid (STA)
radiant lies at 02:58 (044) +11. This position lies on the Aries/Cetus border,
three degrees east of the fourth magnitude star Mu Ceti. The radiant is best
placed near the meridian at 0200 LDT, but activity may be seen all night long.
Striking the atmosphere at 29 km/sec., the average Southern Taurid meteor travels
slowly through the skies. Rates should be near two per hour no matter your location.

A new radiant has been discovered in Taurus which is active during this period.
The Eta Taurids (ETT) are active from October 25 through November 3, with
maximum occurring on the 25th. The current radiant position lies at 03:42 (056)
+24, which lies in western Taurus in the area of sky occupied by the famous
Pleiades star cluster. The radiant is best placed near 0300 LDT, when it lies
highest above the horizon. Meteors from the Eta Taurids strike the atmosphere at
47km/sec., which would produce meteors of average velocity. Expected rates would
be less than one per hour, no matter your location.

The Orionids (ORI) reached maximum activity on the nights of October 21 and
22. Rates are now falling and will do so until the last Orionids are seen near
November 14. The radiant is currently located at 06:34 (98) +16. This position lies
in western Gemini very close to the second magnitude star Alhena (Gamma Geminorum).
The radiant is best placed near 0530 LDT, when it lies highest above the horizon.
Current rates would be near five per hour. At 66km/sec., the average Orionid is swift.

The Epsilon Geminids (EGE) are active from October 16th through the 27th.
Maximum activity occurred on the 19th. The radiant is currently located at 07:09
(107) +27. This position lies in central Gemini, three degrees south of the fourth
magnitude star Tau Geminorum. This position is also close to the Orionid radiant
so care must taken for correct shower association, especially since they have
similar velocities. The Orionids will be more numerous. Current rates are most
likely less than one per hour. The radiant is best placed near 0600 LDT, when it
lies highest above the horizon. At 70km/sec., the average Epsilon Geminid is swift.

Recent studies by Sirko Molau has revealed a radiant in Cancer that is active this
time of year. The Beta Cancrids (BCN) are active from October 25 through
November 3, with maximum occurring on the 27th. The current radiant position lies
at 07:16 (109) -09, which lies in southwestern Canis Minor, seven degrees southwest
of the brilliant zero magnitude star Procyon (Alpha Canis Minoris. The radiant is
best placed near 0600 LDT, when it lies highest above the horizon.Meteors from the
Beta Cancrids strike the atmosphere at 65km/sec., which would produce meteors of
swift velocity. Expected rates would be less than one per hour, no matter your location.

The Leonis Minorids (LMI) are active from October 16-27 with maximum activity
occurring on October 23rd. ZHR’s are usually low but the radiant is far removed
from the Orionids and Epsilon Geminids so that any possible shower members should
be easily identified. Hourly rates should be near one this weekend. This radiant
is currently located at 10:52 (163) +36, which places it in northeastern Leo Minor,
just northwest of the fourth magnitude star 46 Leonis 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 60km/sec., the
average Leonis 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 three 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. Moonlight reduces evening rates this week.

The table below presents a condensed version of the expected activity this week.
Rates and positions are exact for Saturday night/Sunday morning.