(meteorobs) Meteor Activity Outlook for December 27, 2008 - January 4, 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 Saturday December 27th.
At this time the moon lies close to the sun and is not visible at night.
Next week the waxing crescent moon sets during the evening hours and does
not interfere with observing during the more active morning hours. The
estimated total hourly rates for evening observers this week is near four
for those located in the mid-northern hemisphere (45 N) and three for those
viewing from the mid-southern hemisphere (45 S). For morning observers the
estimated total hourly rates should be near twenty for those located in the
mid-northern hemisphere (45 N) and fifteen 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. Evening rates are reduced due to moonlight.

The radiant positions and rates listed below are exact for Saturday
night/Sunday morning December 27/28. 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 07:16 (109) +21. This
area of the sky lies in central Gemini near the fourth magnitude star Delta
Geminorum. This radiant is best placed near 0100 local standard time (LST)
when it lies on the meridian and is highest in the sky. Actually any meteor
from eastern Gemini or western Cancer 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.

The Coma Berenicids (COM) are active from a radiant located at 11:16 (169)
+27. This area of the sky is located in northern Leo, six degrees north of
the 3rd magnitude star Zosma (Delta Leonis). These meteors are best seen
near 0500 LST when the radiant lies highest above the horizon. Rates should
currently be near two per hour as seen from the northern hemisphere and one
per hour as seen from locations south of the equator. At 64 km/sec. the Coma
Berenicids will usually produce meteors of swift velocity.

The Quadrantids (QUA) reach maximum activity near 1300 UT on January 3. This
timing is good for the west coast of North America. The exact maximum is
difficult to catch under perfect conditions where the shower peaks with the
radiant located high in the sky. Most observers will do well seeing rates of
fifty Quadrantids per hour. From high northern latitudes some Quadrantid
activity may be seen during the evening hours but during 2009 the moon will
be above the horizon during the evening hours. A few Quadrantids may be seen
from the equator and low southern latitudes during the small window of time
between the rise of the radiant and the start of morning twilight. At higher
southern latitudes the radiant does not rise until the sky is too bright so
no Quadrantid activity is visible south of approximately 30 degrees south
latitude. The first quarter moon will set near midnight allowing the more
active morning hours to be free of interfering moonlight. On January 3rd the
radiant is located at 15:20 (230) +49. This area of the sky is located in an
empty portion of northeastern Bootes some twenty degrees east of the second
magnitude star Alkaid (Eta Ursae Majoris). The nearest bright star is third
magnitude Beta Bootis, lying eight degrees to the southwest of the
Quadrantid radiant. On the morning of January 4th, the rates will have
dropped back below the sporadic background. The ZHR is back down to one on
January 5th and all traces of the shower disappear by January 13. At 42
km/sec. the Quadrantids produce meteors of average to swift velocity. This
shower is also known as the Bootids.

As seen from the mid-northern hemisphere (45N) one would expect to see
approximately fifteen 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 thirteen per hour as seen from rural observing sites and two per hour
during the evening hours. Locations between these two extremes would see
activity between the listed figures. Evening rates are reduced due to
moonlight.

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) 07:16 (109) +21  Velocity - 30 km/sec.
Northern Hemisphere - 3 Southern Hemisphere - 2

Coma Berenicids (COM)  11:16 (169) +27  Velocity - 64 km/sec.
Northern Hemisphere - 2 Southern Hemisphere - 1

Quadrantids (QUA)  15:20 (230) +49   Velocity - 42 km/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#X2009

Clear Skies!
Robert Lunsford
American Meteor Society