(meteorobs) Meteor Activity Outlook for January 24-30, 2009

[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 it new phase on Monday January 26th. At
this time the moon lies in the vicinity of the sun and is invisible at
night. Late next week the waxing crescent moon appears in the evening sky
but sets soon after the end of twilight. Thus there is no lunar interference
during this period. 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 ten for those located in the
mid-northern hemisphere (45 N) and twelve for those viewing from the
mid-southern hemisphere (45 S). Locations between these two extremes would
see activity between the listed figures. 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 24/25. 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 09:12 (138) +15. This
area of the sky lies on the Leo/Cancer border, twelve degrees northwest of
the first magnitude Regulus (Alpha Leonis). This radiant is best placed near
0100 LST, when it lies on the meridian and is located highest in the sky.
Due to the large size of this radiant, any meteor radiating from Cancer or
western Leo could be a candidate for this shower. Rates at this time should
be near three per hour as seen from the northern hemisphere and two 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.

Later next week the Alpha Centaurids (ACE) become active from a radiant
located at 12:56 (194) -55. This area of the sky is located in southern
Centaurus, six degrees southeast of the second magnitude star Gamma
Centauri. Current rates would be less than one shower member per hour. These
meteors are best seen near 0500 local standard time when the radiant lies
highest above the horizon. This shower is not visible north of 35 degrees
north latitude and also poorly seen in the northern tropics. The southern
hemisphere offers a much better view of this activity as the radiant lies
much higher in the southern sky. Those located at high southern latitudes
will actually encounter morning twilight before the radiant reaches
culmination. At 56 km/sec. the Alpha Centaurids will usually produce meteors
of swift velocity.

The last remnants of the Coma Berenicids (COM) will be seen this week from a
radiant located at 13:00 (195) +16. This area of the sky is located in
southeastern Coma Berenices, two degrees southwest of the fourth magnitude
star Alpha Comae Berenices. These meteors are best seen near 0500 LST when
the radiant lies highest above the horizon. Rates should currently be less
than one per hour no matter your location. At 64 km/sec. the Coma Berenicids
will usually produce meteors of swift velocity.

As seen from the mid-northern hemisphere (45N) one would expect to see
approximately thirteen Sporadic meteors per hour during the last hour before
dawn as seen from rural observing sites. Evening rates would be near two per
hour. As seen from the mid-southern hemisphere (45S), morning rates would be
near fifteen per hour as seen from rural observing sites and three per hour
during the evening hours. Locations between these two extremes would see
activity between the listed figures.

The table below presents a summary of the expected activity this week. Rates
and positions are exact for Saturday night/Sunday morning but may be used
all week.

Antihelion (ANT) - 09:12 (138) +15   Velocity -30km/sec.
Hourly Rates - Northern Hemisphere - 3   Southern Hemisphere - 2

Alpha Centaurids (ACE)  12:56 (194) -55   Velocity - 56km/sec.
Hourly Rates - Northern Hemisphere - <1   Southern Hemisphere - <1

Coma Berenicids (COM)  13:00 (195) +16   Velocity - 64km/sec.
Hourly Rates - 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#X2009

Clear Skies!
Robert Lunsford
American Meteor Society