(meteorobs) Meteor Activity Outlook for January 4-10, 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 new phase on Tuesday January 8. At
this time the moon will be located close to the sun and will not be visible
at night. 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 twenty 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 5/6. 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 07:52 (118) +20. This
area of the sky lies in eastern Gemini, eight degrees south of the first
magnitude star Pollux (Beta Geminorum). 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 eastern Gemini or western 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 3-9, from an area in western Hydra. Maximum occurs on January
4 with the radiant located at 08:32 (128) -13. This position lies fifteen
degrees southwest of the second magnitude star Alpha Hydrae. This radiant is
best placed near 0200 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 39km/sec., the average meteor from this radiant
would be of average velocity.

Sirko Molau's study of video radiants has also revealed activity during the
period January 1-6, from an area in western Leo. Maximum occurred on
January 3 with the radiant located at 09:44 (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 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 55km/sec., the average meteor from this radiant would
be swift.

The Coma Berenicids (COM) are active from a radiant located at 12:40 (190)
+18. This area of the sky is located in a remote area of central Coma
Berenices. The nearest bright star is Denebola (Beta Leonis), located some
fifteen degrees to the southwest. Current rates would be near one shower
member per hour. 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.

The Quadrantids (QUA) reach maximum activity near 0640 UT on January 4. This
timing is good for the Northern Atlantic region including extreme western
Europe and eastern 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. Most of Europe and North America will see maximum
rates of less than fifty per hour. From high northern latitudes some
Quadrantid activity may be seen 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. On January 4th 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 5, the rates have dropped back
below the sporadic background. The ZHR is back down to one on January 6 and
all traces of the shower disappear by January 13. At 41 km/sec. the
Quadrantids produce meteors of average to swift velocity. This shower is
also known as the Bootids.

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.

The table below presents a condensed version of the expected activity this
week. Rates and positions are exact for Saturday night/Sunday morning. Note
that the Quadrantid rates have fallen to near nothing after peaking only two
days prior.

Antihelion (ANT) - 07:52 (118) +20    Velocity 30 km/sec.
Northern Hemisphere - 2   Southern Hemisphere - 1

Alpha Hydrids (Non-IMO Shower)  08:32 (128) -13    Velocity 39 km/sec.
Northern Hemisphere - <1   Southern Hemisphere - <1

Epsilon Leonids (Non-IMO Shower)  09:44 (146) +25   Velocity 55 km/sec.
Northern Hemisphere - <1   Southern Hemisphere - <1

Coma Berenicids (COM)  12:40 (190) +18   Velocity 65 km/sec.
Northern Hemisphere - 1   Southern Hemisphere - <1

Quadrantids (QUA)  15:20 (230) +49  Velocity 41 km/sec.
Northern Hemisphere - 2   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