Meteor Activity Outlook for December 29 2006 – January 4, 2007

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.

This week the moon reaches its full phase
on Wednesday January 3. At this time the moon will be present in the sky all night
long and will interfere with all observing attempts. This weekend the waxing gibbous moon will set
a few hours before dawn allowing a small window of opportunity to view activity in
dark skies. The estimated total hourly rates for evening observers this week is
near three for those located north of the equator and three for observers south of
the equator. For morning observers the estimated total hourly rates should be near
ten for northern observers and six for those located south of the equator.
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. Rates are reduced due to the intense moonlight.

The radiant positions listed below are exact for Saturday
night/Sunday morning December 30/31. 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. This method 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.

These showers are expected to be active this week:

The Antihelion (ANT) radiant is now centered at 07:28 (112) +21. This area
of the sky lies in central Gemini, two degrees east of the third magnitude star
Delta Geminorum. This radiant is best placed near 0100 local standard time when it lies on the
meridian and is highest in the sky. 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 3-9, from an area in western Hydra.
Maximum occurs on January 4 with the radiant located at 8:32 (128) -13. This
position lies fifteen degrees southwest of the second magnitude star Alphard
(Alpha Hydrae).
This radiant is best placed near 0200 LST when it lies highest in the sky.
It appears that four percent of the total sporadic activity for the night is
related to this radiant. This would equate to only 1-2 shower members per hour at
best. With a bright moon in the sky, seeing any activity from this radiant would
be remote. At 39km/sec., the average meteor from this radiant would be of
medium velocity.

Sirko Molau’s study of video radiants has also revealed
activity during the period January 1-5, from an area in western Leo.
Maximum occurs on January 3 with the radiant located at 9:44 (146) +25. This
position lies very close to the third magnitude star (Epsilon Leonis).
This radiant is best placed near 0300 LST when it lies highest in the sky.
It appears that five percent of the total sporadic activity for the night is
related to this radiant. This would equate to only 1-2 shower members per hour at
best. With a bright moon in the sky, seeing any activity from this radiant would
again be remote. At 55km/sec., the average meteor from this radiant would be swift.

The Coma Berenicids (COM) peaked near December 20
with an average ZHR of five. Rates have now fallen to 2-3 per hour as seen from the
northern hemisphere. Bright moonlight will reduce these rates even more. Activity
may be seen from the southern hemisphere, but at a lower rate. The current location
of this radiant is 12:24 (186) +20. This area of the sky is located in central Coma
Berenices border some eight degrees northeast of the second magnitude star Denebola
(Beta Leonis). These meteors are best seen near 0600 local standard time when the
radiant lies highest above the horizon. At 5 km/sec. the Coma Berenicids will
usually produce meteors of swift velocity.

The Quadrantids (QUA) The Quadrantids will peak
near 00:30 Universal Time on January 4, 2007. This timing
favors central Asia where the radiant will be located highest in a dark sky. For
North America this time corresponds to 07:30 PM EST and 04:20 PM PST on the evening of January 3.
Some evening activity may be seen from North America but counts will be low due to
the low altitude of the radiant at this time. The radiant is located at 15:20 (230)
+49. This area of the sky lies in northern Bootes in an area southeast of the handle
of the “Big Dipper”. This area of the sky is located low in the northwestern sky
at dusk. It reaches it lowest point below the pole star near 1900 local standard
time and then begins its slow ascent into the northeastern sky. It is best placed
during the last hour before dawn when it lies approximately half-way up in the
northeastern sky. This is when most of the activity will be seen.

Unfortunately the moon will be full on January 3, and will severely limit the
number of meteors that will be seen. The moon will be in the sky all night and
will affect counts no matter the time of night. When viewing this display it would
be best to face toward the northern half of the
sky. If hills or lights obscure your northern horizon then switch toward a more
easterly view. Whatever direction you face, be sure to look approximately half-way up
into the sky. Most of the meteor activity occurs in the lower half of the sky so
place the lower portion of your field of view just above the horizon or trees to
see the best activity. Observers in the Southern Hemisphere will see very little
Quadrantid activity as the radiant will not rise sufficiently in altitude before
the onset of morning twilight. All Quadrantid meteors will trace back to the
radiant area in Northern Bootes. There will be other showers and random activity
visible during this period so not all meteors will be members of the Quadrantid
shower. Quadrantid meteors will appear to travel swiftly through the sky unless
they are seen near the radiant or near the horizon. Quads seen there will move
more slowly as they are moving towards you (if seen near the radiant) or away
from you (if seen near the horizon). It is of great importance is to be warm and
comfortable while viewing these meteors. Running outside for just a quick peek
will not provide any satisfaction.

This shower is named for the obsolete constellation Quadrans Muralis (Murals Quadrant),
which once occupied the area of northern Bootes. Some meteor organizations refer
to this shower as the Bootids. It is thought that this shower is related to the
recently discovered asteroid 2003 EH1. Peter Jenniskens, who discovered this
relationship, states that this object is most likely an extinct comet nucleus that
appears to be the remnant of a larger object that broke up about 500 years ago.
The Earth intersects the orbit of this object near January 4 each year. The Earth
intersects this orbit at a perpendicular angle which means we quickly move through
any debris produced by this object. ZHR’s in excess of one are produced for only
five days centered on the time of maximum activity. This will be the last opportunity
to see a major annual shower until the Lyrids of April.

Sporadic rates have passed the late year plateau
for observers located in the northern hemisphere. One would expect to see perhaps
five random meteors during the last hour before dawn from rural observing sites.
During the first dark hour after the end of evening twilight, perhaps three random
meteors can be seen per hour. Sporadic rates increase as the night progresses so
rates seen near midnight would be near four per hour. Sporadic rates seen from the
southern hemisphere have passed their annual minimum and are rising again. One
would expect to see approximately five random meteors per hour during the last hour
before dawn and three per hour during the first dark hour after the end of evening
twilight. Rates near midnight would be near four per hour. All rates are reduced
due to the intense moonlight.

Active Showers and Rates for the Weekend of 12-30/31