(meteorobs) Meteor Activity Outlook for November 8-14, 2008

Robert Lunsford lunro.imo.usa at cox.net
Sat Nov 8 13:08:11 EST 2008

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 from south of the equator, but the sporadic rates are much
lower than those seen in the northern hemisphere.

During this period the moon reaches its full phase on Thursday November
13th. At this time the moon will be in the sky all night long and will
severely hamper meteor observing. This weekend and early next week there is
a window of opportunity when one can observe in dark skies. During this
period the waxing gibbous moon will set before the start of morning
twilight. This window decreases as this period progresses until it is near
zero on Wednesday November 12th. The estimated total hourly rates for
evening observers this week is near three for those located in the
mid-northern hemisphere (45 N) and two for those viewing from the
mid-southern hemisphere (45 S). For morning observers the estimated total
hourly rates should be near ten for those located in the mid-northern
hemisphere (45 N) and six 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. Rates are
reduced during this period due to moonlight.

The radiant positions and rates listed below are exact for Saturday
night/Sunday morning November 8/9. 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 Pisces and
then into Andromeda between November 1st and the 19th, peaking on the 5th.
The position at maximum activity is 01:32 (023) +30. This position lies on
the Pisces-Triangulum border, four degrees west of the third magnitude star
Alpha Trianguli. Visual activity is expected to be low, but detectable. The
Andromedid radiant is best placed near 2200 (10pm) local standard time
(LST). At 20km/sec., the average Andromedid will appear as a very slow
moving meteor. Sirko mentions that these meteors are "conspicuously slow and
of almost constant activity" during this period.

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
03:40 (055) +22. This position lies in western Taurus some three degrees
southwest of the famous naked eye open star cluster known as the Pleiades or
the Seven Sisters. The center of the large Southern Taurid (STA) radiant
lies at 03:40 (055) +15. This position also lies in western Taurus,
approximately ten degrees southwest of the Pleiades. The two radiants are
separated by approximately seven 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 0100 LST. 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

The Leonids (LEO) are just now coming to life from a radiant located at
09:48 (147) +24. This position lies in western Leo, very close to the
position of the third magnitude star Epsilon Leonis. Maximum activity is
predicted to occur on November 19 so current rates would most likely be less
than one 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 Leo is swift with a high
percentage of trains. The radiant is most favorably located during the last
dark hour before the onset of morning twilight.

As seen from the mid-northern hemisphere (45N) one would expect to see
approximately eight Sporadic meteors per hour during the last hour before
dawn as seen from rural observing sites. Evening rates would be near two per
hour. As seen from the mid-southern hemisphere (45S), morning rates would be
near three 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. Sporadic rates are reduced during this
period due to moonlight.

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.

Andromedids (AND)  01:32 (023) +30   Velocity - 20km/sec.
Hourly Rates:  Northern Hemisphere - <1  Southern Hemisphere - <1

Northern Taurids (NTA)  03:40 (055) +22   Velocity - 29km/sec.
Hourly Rates:  Northern Hemisphere - 2  Southern Hemisphere - 2

Southern Taurids (STA)  03:40 (055) +15   Velocity - 27km/sec.
Hourly Rates:  Northern Hemisphere - 1  Southern Hemisphere - 1

Leonids (LEO) 09:36 (144) +29  Velocity - 71km/sec.
Hourly Rates:  Northern Hemisphere - <1  Southern Hemisphere - <1

*For a detailed explanation on the different classes of meteor showers and
other astronomical terms, please visit:

Clear Skies!
Robert Lunsford
American Meteor Society

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