The moon is new on Saturday February 1. At this time the moon will be near the sun (as seen from Earth) and will therefore not be visible at night. Toward the end of this period the moon will be a thin crescent, not causing much of a problem at all as it sets during the early evening hours. The estimated total hourly rates for evening observers this week should be near 3 for everyone regardless of location. For morning observers the estimated total hourly rates should be near 12 for those located in the Northern Hemisphere and 20 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.
The positions listed below
are exact for Saturday night/Sunday morning February 1/2. The positions do
not change greatly day to day so these 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 radiants below are
listed in a west to east manner in order of right ascension (celestial longitude).
The radiants 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 following radiants will be
active this week:
The Alpha Carinids
are listed among the radiants of the Dutch Meteor Society. The date of maximum
activity was January 30 with a predicted ZHR of 2. Current rates would be
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 06:24 (096) -54. This position lies in extreme western Carina
just two degrees south of the brilliant negative one magnitude star Canopus
(Alpha Carinae). Due to the far
southern declination (celestial latitude) this shower is not well seen north
of the northern equatorial regions. The
area of the sky is best placed near 2200 (10pm) local standard time when
it lies highest in the sky. At 25 km/sec. the Alpha Carinids produce meteors
of slow velocity.
The Antihelion source is now centered at 9:48 (147) +13. This area of the sky is located in western Leo some four degrees west of the first magnitude star Regulus (Alpha Leonis). Since this source is large and diffuse, any slow to medium speed meteor from eastern Cancer or western Leo could be a candidate for this shower. The 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 2 shower members per hour from all locations.
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 share their reports with the I.M.O.
should call these meteors Virginids or "VIR".
The Northern Apex source is now centered at 14:48 (222) -00. This position lies on the Virgo/Libra border some 10 degrees northwest of the third magnitude star Zubeneschamali (Beta Librae). This area of the sky is best placed for viewing during the last dark hour before dawn. Since this source is large and diffuse any meteors from eastern Virgo, northwestern Libra, southern Serpens Caput or southeastern Bootes could be a good candidate for this shower. This source should provide at least 2 meteors per hour no matter your location.
Like the antihelion source 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. 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 could 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 14:48 (222) -30. This position lies on the Hydra/Centaurus
border two degrees south of the fourth magnitude star 58 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 northern Centaurus,
eastern Hydra or southern Libra could a candidate from this source. Rates
should be near 3 per hour from the Southern Hemisphere and less than 1 per
hour from the Northern Hemisphere.
The Sporadic rates for the Northern Hemisphere are now slowly declining and will do so until June. One would currently expect to see perhaps 8 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 2 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 9 random meteors being seen per hour during the early morning hours and 2 per hour during the evening.
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 not be a
hindrance until February 13 and afterward, when it will still be in the sky
after 0200 local standard time.
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 be 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!