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(meteorobs) Meteor Activity Outlook for Jan 30-Feb 5, 2004



The moon reaches its full phase on Friday February 6. At this time the moon
lies opposite the sun in the sky and is above the horizon most of the night.
This weekend the waxing gibbous moon will set during the early morning hours
and allow a few hours of observing before the onset of morning twilight. The
estimated total hourly rates for evening observers this week should be near
two for those in the Northern Hemisphere and three for those south of the
equator. For morning observers the estimated total hourly rates should be
near twelve for those located in the Northern Hemisphere and sixteen for
those 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 meteor
activity.  Evening rates are reduced due to moonlight.

The radiant positions listed below are exact for Saturday night/Sunday
morning January 31/February 1. The radiants do not change greatly day to day
so the given positions may be used during this entire period. Most star
atlases (available at science stores and libraries) 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 location. 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 last rise later in the night. This list also
provides the order of ascending velocity for each radiant with those listed
first usually being much slower than those last on the list. Velocity should
not be the prime factor for shower association as all showers can produce
slow meteors. Slow meteors can be produced from normally swift showers, such
as the Leonids, when meteors appear near the radiant or close to the
horizon. The true velocity is only revealed in shower members seen far from
the radiant and high in the sky.

The Alpha Carinids (ACN) is a shower listed among radiants of the Dutch
Meteor Society. The date of maximum activity is January 31 with a predicted
ZHR of two. Current rates would be most likely less than one shower member
per hour. With such low activity care must be taken to exclude any sporadic
activity from the Alpha Carinid count. The radiant currently lies at 06:20
(095) -54. This position lies in western Carina, only one degree south of
the brilliant negative one magnitude star Canopus (Alpha Carinae). This
radiant is only seen well from the northern equatorial regions southward.
The area of the sky is also best placed near 2200 (10pm) local standard
time. At 25 km/sec. the Alpha Carinids produce meteors of slow velocity.

The Delta Velids (DVE) is another shower listed among radiants of the Dutch
Meteor Society. The date of maximum activity is February 15 with a predicted
ZHR of one. Current rates would be less than one shower member per hour.
With such low activity care must again be taken to exclude any sporadic
activity from the Delta Velid count. The radiant currently lies at 08:16
(124) -48. This position lies in western Vela , very close to the second
magnitude star Gamma Velorum. Like the Alpha Carinids, this radiant is only
seen well from the northern equatorial regions southward. The area of the
sky is also best placed near midnight local standard time. At 35 km/sec. the
Delta Velids produce meteors of average velocity.

The Alpha Hydrids (AHY) is another shower listed among radiants of the Dutch
Meteor Society. The date of maximum activity was January 15 with a predicted
ZHR of two. Current rates would be most likely less than one shower member
per hour. With such low activity care must be taken to exclude any sporadic
activity from the Alpha Hydrid count. The radiant currently lies at 09:36
(144) -16. This position lies in western Hydra seven degrees south of the
second magnitude star Alphard (Alpha Hydrae). This radiant is seen equally
well from both hemispheres. The area of the sky is also best placed near
0200 local standard time. At 44 km/sec. the Alpha Hydrids produce meteors of
average velocity.

The Antihelion radiant is now centered at 09:44 (146) +13. This area of the
sky is located in western Leo some seven degrees northwest of the first
magnitude star Regulus (Alpha Leonis). Since this radiant is large and
diffuse, any slow to medium speed meteor from eastern Cancer or western Leo
could be a candidate for this shower. The center of this area 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 two shower members per hour from areas
north of the equator and one per hour for locations south of the equator.

Unlike most of the annual showers the antihelion source is produced by
debris from unknown objects orbiting in a direct motion like the earth.
These objects are most likely asteroids, which produce stony and metallic
debris whose density is much greater than material produced by comets. This
material collides with the earth on the inbound portion of its orbit, before
its closest approach to the sun. Therefore we best see them just after
midnight when we are facing the direction from which this activity appears.
The antihelion source is active all year from an area of the sky nearly
opposite that of the sun. The center of this source will move approximately
one degree eastward per day and travels through many different
constellations over the course of a year. It may make sense to list these
meteors as antihelions or "ANT" but a majority of meteor organizations
prefer that you list them from the constellation in which the radiant is
currently located or the constellation where the shower reaches maximum
activity. Those who send their data to the International Meteor Organization
should call these meteors Virginids (VIR).

The Omicron Centaurids are one of several radiants that are active in
Centaurus during late January and throughout the month of February. The date
of maximum activity is February 15 with a predicted ZHR of two. Current
ZHR's would be less than one. The radiant lies at 10:52 (163) -50. This
position is in eastern Vela, two degrees southeast of the fourth magnitude
star Mu Velorum. Due to the southern declination this shower is not well
seen north of the northern tropical regions. This area of the sky is best
placed near 0300 local standard time when it lies highest in the sky. At 51
km/sec. the Omicron Centaurids produce meteors of medium-swift velocity.

The Theta Centaurids is the first of several radiants that are active in
Centaurus during late January and throughout the month of February. The date
of maximum activity is February 15 with a predicted ZHR of four. Current
ZHR's would be near one. The radiant lies at 12:52 (193) -35. This position
is in northwestern Centaurus, close to the faint star P Centauri. This
shower is not well seen north of the northern tropical regions. It is
possible to see activity from the latitude of San Diego, CA as I have
witnessed several of these meteors during my winter observations. This area
of the sky is best placed near 0500 local standard time when it lies highest
in the sky. At 60 km/sec. the Theta Centaurids produce meteors of swift
velocity.

The Alpha Centaurids are the strongest of the radiants that are active in
Centaurus during late January and throughout the month of February. The date
of maximum activity is February 9 with a predicted ZHR of seven. Current
ZHR's would be near three. The radiant lies at 13:12 (198) -56. This
position is in southwestern Centaurus four degrees southwest of the second
magnitude Epsilon Centauri. Due to the southern declination this shower is
not well seen north of the northern equatorial regions. This area of the sky
is also best placed near 0500 local standard time when it lies highest in
the sky. At 56 km/sec. the Alpha Centaurids produce meteors of swift
velocity.

The Northern Apex radiant is now centered at 14:44 (221) 00. This position
lies in eastern Virgo, one degree south of the faint star 109 Virginis. This
area of the sky is best placed for viewing during the last dark hour before
dawn when it lies highest in the sky. Since this radiant is large and
diffuse, any meteor from eastern Virgo, southwest Serpens Caput,
northwestern Libra or southeastern Bootes could be a candidate from this
source. Rates would be now close to two per hour regardless of your
location.

Like the antihelion area, both apex areas 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. This is
not really a "shower" per se, but an artificial radiant created by the
Earth's motion through space. Meteors from both branches are normally
included in the sporadic count. I feel it is a worthy project to see if it
is possible to distinguish these meteors from the normal sporadic
background. On rare occasions there are meteors with a zero inclination that
radiate precisely from the apex point on the ecliptic, exactly 90 degrees
west of the sun. In simplistic terms, these meteors are seldom seen since
the Earth "sweeps clean" much of the material that shares the same orbit as
our planet. Much more material 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.

The Southern Apex source lies exactly 30 degrees south of its northern
counterpart at 14:44 (221) -30. This position lies in western Centaurus some
two degrees southwest of the fourth magnitude star 58 Centauri. Like the
northern apex, these meteors are best seen toward dawn when the radiant lies
highest above the horizon in a dark sky. Since this radiant is also large
and diffuse, any meteor from northern Centaurus, southwestern Libra, eastern
Hydra, northern Lupus or southern Virgo could be a candidate from this
source. Rates would be now be less than one per hour in the Northern
Hemisphere and three per hour in the Southern Hemisphere.

The Sporadic rates for the Northern Hemisphere are now past their annual
peak. One would currently expect to see perhaps seven random 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 one
random meteors can be seen per hour from the Northern Hemisphere. Rates seen
from the Southern Hemisphere are now slightly stronger than those seen in
the northern skies with perhaps eight random meteors being seen per hour
during the early morning hours and two per hour during the evening.  Evening
rates are reduced due to moonlight.

Possible activity in Bootes-Corona Borealis-Serpens Caput? There have been
reports of activity in and around this area in late January and early
February. George Gliba was the first to notice this activity during the mid
90's. Intensified video studies by the IMO in 2000 revealed two radiants;
one in Serpens Caput and another located in Corona Borealis during the first
week of February. Observers are urged to keep a look out for this activity
now through mid-February. The two IMO radiants are located at 15:32 (233)
+30 and 15:44 (236) +13. The northern radiant is located within the "crown"
close to the star Beta Coronae Borealis. The more southern radiant is
located near the "head" of Serpens two degrees south of Beta Serpentis.
Another area of possible activity would lie in eastern Bootes between
Arcturus and Xi Bootis. This area of the sky is too low until 0200 local
standard time. The waxing moon will be a hindrance after January 31, when it
will still be in the sky after 0200 local standard time. There will be at
least one hour of complete darkness between moonset and the start of morning
twilight up to February 4. After this date, the moon will be in the sky
during the entire observing window.

Any suspected shower members would appear to move slowly if seen near the
radiant or near the horizon. Those seen high in the sky and far from the
radiant will appear to be swift. Meteors seen near the radiant would also be
short. If you are facing the radiants and see a long meteor close to the
radiant(s) then that meteors is sporadic or belongs to another shower.
Plotting, photographic and video observations are of prime importance to try
to help us determine shower association. Your efforts in trying to help us
verify this activity and its exact radiant would be extremely appreciated.

Clear Skies!
Robert Lunsford
AMS Operations Manager

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