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(meteorobs) Meteor Activity Outlook for November 17-23, 2000
The moon reaches last quarter on Saturday November 18. At this phase
interfering moonlight is limited to observers of the morning sky. As the
week progresses the waning moon becomes less and less of a problem. The
positions listed below (except for the Leonids) are exact for Saturday
night/Sunday morning November 18/19. The positions do not change greatly
day to day so these positions may be used during this entire period.
The Delta Eridanids may provide weak activity from a radiant located at
04:04 (061) -01. This position is located on the Eridanus/Taurus
border roughly 25 degrees south of the Pleiades star cluster. This area
of the sky is well placed for observing near midnight local time. Any
possible shower members would appear to travel slower than your
average meteor.
The Antihelion radiant is now centered at 4:48 (072) +22. This position
lies in central Taurus between the 4th magnitude stars Iota and Tau
Tauri. This area of the sky is best placed near 0100 local time when it
lies on the meridian. Like the Delta Eridanids, these meteors are on the
slow side. Those observers reporting to the IMO should classify these
antihelion meteors as North or South Taurids. Those meteors appearing to
come from Northern Taurus, Southern Auriga, or southern Perseus would be
associated with the NTA's. Those appearing to come from southern Taurus
or western Orion would be associated with the STA's.
The Alpha Monocerotids is a shower of short duration, like the Leonids.
They are active for a week centered on November 20. They have a very
sharp maximum which will occur near 0800 Universal Time on November 21.
This time is favorable for all of North and South America. I would not
expect to see much activity but if it occurs it will most likely happen
near this time. The radiant is located at 07:40 (115) +01. This
position actually lies in southern Canis Minor just 4 degrees south of
the brilliant star Procyon (Alpha Canis Minoris). This portion of the
sky is best placed near 0400 local time. Shower members are swift if
seen high in the sky and far from the radiant. The AMO's have an
interesting history as it seems to possess a 10 year period. Any year
ending with a "5" has a good chance for an outburst. In 1995 the ZHR was
near 500 but unfortunately these rates lasted only 5 minutes! I would
expect more like 1 or 2 per hour this year.
The Zeta Puppids may be active from a radiant located at 08:04 (121)
-43. This position lies on the Puppis/Vela border between the bright
stars Zeta Puppis and Gamma Velorum. Activity from this radiant would be
difficult to detect from the Northern Hemisphere. Those situated south
of the equator have a much better chance of seeing any of this activity.
This radiant is highest in the sky near 0400 local time. Shower members
would appear to travel slowly if seen near the radiant or low in the
sky. Those appearing far from the radiant and high in the sky would be
of medium velocity.
The Northern Apex is now located at 09:48 (147) +28. This position lies
in northwestern Leo near the star Upsilon Leonis. This is just outside
the "sickle" of Leo only 5 degrees from the Leonid radiant. There is a
real chance of some these meteors mistakenly being called Leonids. There
is no real way a visual observer can separate these two showers so it
would be best this week to call these meteors Leonids, since a great
majority of this activity will actually belong the the Leonids. Having
the moon nearby certainly will not help the situation!
The Southern Apex source lies exactly 30 degrees south of its northern
counterpart at 09:48 (147) -02. This position lies in western Sextans
some 8 degrees northeast of the bright star Alphard (Alpha Hydrae). Any
swift meteor from Sextans, Hydra, or even southern Leo has a good chance
of being from this source. As seen from the Northern Hemisphere this
source should produce 1-2 meteors per hour near dawn. Similar rates
would be seen from the Southern Hemisphere.
The Leonids will reach maximum activity on November 17 at 0800 Universal
Time. There are also secondary maximums the following night which could
be stronger than the primary maximum. On the 17th the radiant will be
located at 10:12 (153) +22. This position is located within the
"sickle" of Leo near the stars Xi and Gamma Leonis. This part of the sky
rises during the late evening for observers in the Northern Hemisphere.
Below the equator it will rise during the early morning. The exact time
it rises depends on your geographical coordinates.
Eastern North America and western South America are favored for the
primary maximum on the 17th. 0800 UT corresponds to 0400 local time in
central South America, 0300 in western South America and the east coast
of North America, 0200 for those in CST, 0100 for those in MST, and
midnight for those in PST. Those who are located in an area where the
radiant is situated high in their sky at this time will see the most
activity. At this time the earth will be passing the node of comet
Temple-Tuttle and the dust trails left behind in 1965 and 1932 by this
same comet. No one know for sure just how active the shower may be. We
can be fairly certain that if any enhanced activity occurs this
night it will be near this time. Don't expect a major display since the
earth only skims the outermost portions of these dust trails plus the
bright waning gibbous moon will be close to the radiant.
On the following night (November 18th) there is another possibility for
enhanced rates occurring at 0345 UT. Northwestern Africa and western
Europe are favored for this display. 0345 corresponds to 0445 local time
in continental Europe and 0345 in the British Isles, Portugal, and
western Africa. At this time the earth will be close to the dust trail
created in 1733. Rates could be higher than those seen on the previous
morning. No one knows for sure!
Some four hours later at 0751 UT the earth will pass the dust trail left
behind in 1866. Favorable locations are identical to those on the 17th.
Once again rates could be stronger than those seen on the previous
morning. Only by viewing will we know for sure!
The Sporadic rates for the Northern Hemisphere are past their annual
maximum. With interference from the waning moon one would expect perhaps
6-8 random meteors per hour during the last hours before dawn. During
the dark evening hours perhaps 4 random meteors can be seen per hour.
Rates seen from the Southern Hemisphere would be roughly 50-75% of the
northern rates.
Clear Skies!
Robert Lunsford
AMS Visual Program Coordinator
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