(meteorobs) Meteor Activity Outlook for January 11-17, 2008

[Robert Lunsford]

January sees a peak of sporadic activity for the southern hemisphere while
rates seen north of the equator begin a steady downward turn that continues
throughout the first half of the year. The sporadic activity is good for
both hemispheres, but not as good as it was for northern observers in
December. Once the Quadrantids have passed the shower activity for January
is very quiet.

During this period the moon reaches its first quarter phase on Tuesday
January 15. At this time the moon will be located 90 degrees east of the sun
and will set near midnight. The estimated total hourly rates for evening
observers this week is near two no matter your location. For morning
observers the estimated total hourly rates should be near seventeen for
those located in the mid-northern hemisphere (45 N) and sixteen for those
viewing from the mid-southern hemisphere (45 S). 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 radiant positions and rates listed below are exact for Saturday
night/Sunday morning January 12/13. 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:

The wide Antihelion (ANT) radiant is now centered at 08:20 (125) +18. This
area of the sky lies in central Cancer, five degrees west of the fourth
magnitude star Delta Cancri. This radiant is best placed near 0100 local
standard time when it lies on the meridian and is highest in the sky.
Actually any meteor from Cancer could be a candidate for this shower. Rates
at this time should be near two per hour as seen from the northern
hemisphere and one per hour for observers located south of the equator. With
an entry velocity of 30 km/sec., the average Antihelion meteor would be of
medium-slow speed.

Sirko Molau's study of video radiants has revealed activity during the
period January 13-19, from an area in west-central Coma Berenices. This
position is similar to the Coma Berenicids but far enough away to be
monitored by visual means. Maximum occurs on January 16 with the radiant
located at 12:24 (186) +19. This position lies ten degrees northeast of the
second magnitude star Denebola (Beta Leonis). This radiant is best placed
near 0500 LST when it lies on the meridian and is highest in the sky. Rates
are most likely less than one shower member per hour no matter your
observing location. At 60km/sec., the average meteor from this radiant would
be swift.

The Coma Berenicids (COM) are active from a radiant located at 13:08 (197)
+15. This area of the sky is located in a remote area of eastern Coma
Berenices. The nearest bright star is Arcturus (Alpha Bootis), located some
fifteen degrees to the northeast. Current rates would be near one shower
member per hour no matter your location. These meteors are best seen near
0600 local standard time when the radiant lies highest above the horizon. At
65 km/sec. the Coma Berenicids will usually produce meteors of swift
velocity.

Sporadic rates are now slowly falling for observers in the northern
hemisphere and rising for those located south of the equator. One would
expect to see approximately fourteen random meteors during the last hour
before dawn from rural observing sites no matter your geographic location.
During the first dark hour after the end of evening twilight, perhaps two
random meteors can be seen per hour.

Antihelion (ANT) - 08:20 (125) +18   Velocity - 30km/sec.
Northern Hemisphere - 2   Southern Hemisphere - 1

January Coma Berenicids (Non-IMO Shower)  12:12 (183) +18
Velocity - 60km/sec.
Northern Hemisphere - >1   Southern Hemisphere - >1

Coma Berenicids (COM)  13:08 (197) +15  Velocity - 65km/sec.

Northern Hemisphere - 1   Southern Hemisphere - 1

*For a detailed explanation on the different classes of meteor showers and
other astronomical terms, please visit:
http://www.amsmeteors.org/showers.html#X2008

Clear Skies!
Robert Lunsford
American Meteor Society