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(meteorobs) Meteor Activity Outlook for November 16-22, 2001

The moon reaches its first quarter phase on Thursday November 22th. This
weekend the waxing crescent moon will set soon after the end of evening
twilight. This will allow observers idea conditions for watching the
rise and fall of the Leonid meteor shower. The estimated total hourly
rates for evening observers this week should be near 3 for those in the
Northern Hemisphere and 1 for those in the Southern Hemisphere. For
morning observers the estimated average total hourly rates should be
near 35 for the Northern Hemisphere and 20 for those located in the
Southern Hemisphere. 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 for
meteor activity. The positions listed below are exact for Saturday
night/Sunday morning November 17/18. The positions do not change greatly 
day to day so they may be used during this entire period.

The Delta Eridanids are listed among the radiants of the Dutch Meteor
Society. This very weak shower peaked on November 12 with an estimated
ZHR (zenith hourly rate) of 1. The radiant position lies at 03:56 
(059) -01. This area of the sky lies in north central Eridanus a 7
degrees south of the 4th magnitude star Nu Tauri. Any slow meteor from
this area or southern Taurus may be a shower member. Do not confuse this
activity with that of the antihelion radiant located to the northeast.
The antihelion radiant will produce much more activity. These meteors
will be best seen near midnight local standard time when it lies on the
meridian and is highest in the sky.

The Antihelion radiant is now located at 04:44 (071) +22. This area of
the sky is located in central Taurus close to the 4th magnitude star Tau
Tauri. Any slow to medium speed meteor from Taurus may be a good 
candidate for this shower.  This area of the sky is best placed near
0100 local standard time when it lies on the meridian and is highest in
the sky. At this time expect to see at least 5 shower members per hour
from most locations. We are now seeing an increase in the antihelion
activity as the earth encounters debris from comet 1P Encke.  Observers
who share their reports with the International Meteor Organization
(I.M.O.) should label these meteors as "North or South Taurids",
depending if they appear to radiate from north or south of the ecliptic.

There is the possibility that a radiant in Auriga may be producing
activity during the same time as Leonids. The possible "Iota Aurigids"
have a radiant near 5:00 (075) +37. This area of the sky is located in
western Auriga near the faint star Omega Aurigae. Any possible meteors
from this shower would have a medium velocity if seen far from the
radiant and high in the sky. If seen close to the radiant or close to
the horizon they would appear to move more slowly. While this radiant is
in the sky most of the night for Northern Hemisphere observers, it is
best placed near 0100 when it lies highest above the horizon. Quoted
ZHR's lie between 14-20, but if it were truly this high this radiant
should have been discovered long ago. I would expect much lower rates 
less than 5 per hour.

The Alpha Monocerotids reach maximum activity on November 21. The
current radiant position lies at 07:36 (114) +01 which places it on the
Monoceros/Canis Minor border some 5 degrees south of the brilliant white
star Procyon (Alpha Canis Minoris). This shower usually produces very
minor activity except in years ending in "5". In 1995 the shower
produced a brief outburst with rates in excess of 400/hr. Unfortunately
this year the best rates will be only 1 or 2 shower members per hour.
Shower members are swift when seen high in the sky far from the radiant.
The best time to look for this activity is between 0300 and 0400 local
standard time when the radiant lies highest above the horizon.

The Zeta Puppids is another radiant listed among the radiants of the
Dutch Meteor Society. This weak shower peaked on November 13th. The
current radiant position is located at 08:04 (121) -43. This area of the
sky is located in southeastern Puppis 4 degrees southeast of the 2nd
magnitude star Xi Puppi. This radiant is better placed for observers
located south of the equator when it is seen much higher in the sky.
These observers may see 2-3 shower members per hour at maximum. The
radiant is best placed in the sky near 0400 when it lies highest in the
sky. Any shower members would be of medium speed if seen far from the
radiant and high in the sky. If seen close to the radiant or low in the
sky they would appear to move more slowly.

The Northern Apex radiant is now located at 09:44 (146) +28. This
position lies in northwestern Leo 2 degrees northeast of the 5th
magnitude star Kappa Leonis. This position lies 10 degrees northwest of
the Leonid radiant. This area of the sky is best placed for viewing
during the last dark hour before dawn. Since this radiant is diffuse any
meteors from northern Cancer, southeastern Lynx or northwestern Leo
could be a good candidate. As seen from the Northern Hemisphere this
source should produce 2-3 meteors per hour during the last few hours
before dawn. Rates seen from the Southern Hemisphere would be much less
at 0-1 per hour due to the low radiant altitude seen south of the
equator. It will be difficult if not impossible to separate these 
meteors from the Leonids. Both radiants produce swift, often trained
meteors. At this time odds are that any activity will belong to the
Leonids and not the northern apex radiant .

Like the antihelion radiant both apex radiants are active all year long
and travel approximately one degree eastward per day. Unlike the
antihelion debris these particles orbit the sun in a retrograde motion
opposite that of the earth and are most likely produced by unknown
comets. They strike the earth after their closest approach to the sun.
Since they are moving in opposite directions these particles strike the
earth at tremendous velocities often creating bright meteors with
persistent trains. These particles strike the earth on the morning side
of earth and are best seen just before morning twilight while the sky is
still perfectly dark. There are meteors with a zero inclination that
radiate precisely from the apex point on the ecliptic, exactly 90
degrees west of the sun. These meteors are rare though as the earth
orbits the sun it "sweeps clean" much of the material that shares the
same orbit. Much more debris is located just north and south of the
earth's orbit with slightly higher or lower inclinations. This creates
the northern and southern branches of the apex activity. Meteors from
both branches are normally included in the sporadic count but should
also be noted in some manner as to which branch of the apex complex they
appear to radiate.

The Southern Apex source lies exactly 30 degrees south of its northern
counterpart at 09:44 (146) -02. This position lies in western Sextans,
some 2 degrees west of the 4th magnitude star Iota Hydrae. Like the
northern apex these meteors are best seen toward dawn when the radiant
lies highest above the horizon in a dark sky. Any meteor from western
Hydra, Sextans or southwestern Leo could be a candidate from this
source. Rates should be close to 2 per hour from most locations.
Leonid activity reaches maximum on November 18 from a radiant located at
10:12 (153) +22. This area of the sky is located within the "sickle of
Leo" only 2 degrees northwest of the famous 2nd magnitude star Algeiba 
(Gamma Leonis). The radiant does not rise until near midnight from most
locations so it is impossible to see any Leonid activity during the
early evening hours. The Leonids are very swift meteors when seen far
from the radiant and high in the sky. They will appear to move more
slowly if seen near the radiant or low in the sky. For more information
on viewing the Leonids visit the AMS web site at:
http://www.amsmeteors.org/

The Sporadic rates for the Northern Hemisphere are now near 8 meteors
per hour during the last hours before dawn from rural observing sites.
This estimate and the morning estimate for the Southern Hemisphere does
not include the apex meteors listed above. During the evening hours
perhaps 3 random meteors can be seen per hour from the Northern
Hemisphere. Rates seen from the Southern Hemisphere are now at their
annual low with perhaps 4 random meteors being seen per hour during the
late morning hours and 1 per hour during the evening.

Clear Skies!
Robert Lunsford
AMS Visual Program Coordinator
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