(meteorobs) Meteor Activity Outlook for December 5-11, 2009

[Robert Lunsford]

No matter where you live, the first half of December provides some of the best meteor activity of the year. In the northern
hemisphere the sporadic rates are still strong plus you can also count on strong activity from the Geminids, which peak on December
13. There are also several minor radiants that add a few meteors each hour. All of these centers of activity are located high in the
sky during the early morning hours this time of year. Unfortunately this year the bright moon spoils the show during the first week
of the month. During the second week of December the moon will pass its last quarter phase and will not be such a nuisance .

As seen from the southern hemisphere the sporadic rates are increasing toward a January maximum. Shower rates are also good but the
Geminids suffer a bit from the lower elevation seen from southern locations. Still with the warmer weather now occurring south of
the equator, December is a great time to view celestial fireworks.

During this period the moon reaches its last quarter phase on Wednesday December 9th. On that date the moon lies ninety degrees west
of the sun and rises near midnight local standard time (LST). This weekend the waning gibbous moon will rise during the evening
hours and remain in the sky the remainder of the night. The bright glare from the gibbous moon will make it difficult to view any
meteor activity. Once the moon passes its last quarter phase the moonlight becomes less of a problem. The estimated total hourly
rates for evening observers this week is near three as seen from the northern hemisphere and two from the southern hemisphere. For
morning observers the estimated total hourly rates should be near ten from the northern hemisphere and seven as seen from the
southern hemisphere. 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. Morning rates are reduced during this period due to moonlight.

The radiant positions and rates listed below are exact for Saturday night/Sunday morning December 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 full descriptions of each active meteor shower will continue next week when the moon becomes less of a nuisance to observers.

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

Phoenicids (PHO)  - 01:12 (018) -53   Velocity - 18km/sec.
Northern Hemisphere -<1 per hr. Southern Hemisphere - <1 per hr.

Northern Taurids (NTA)  - 05:16 (079) +26    Velocity - 29km/sec.
Northern Hemisphere - 2 per hr. Southern Hemisphere - 1 per hr.

Monocerotids (MON) - 06:32 (098) +08   Velocity - 41km/sec.
Northern Hemisphere - <1 per hr. Southern Hemisphere - <1 per hr.

Geminids (GEM)  - 07:10 (107) +33   Velocity - 35km/sec.
Northern Hemisphere - 2 per hr. Southern Hemisphere - <1 per hr.

Puppid-Velids (PUP)  - 08:10 (122) -45 Velocity - 40km/sec.
Northern Hemisphere - <1 per hr. Southern Hemisphere - <1 per hr.

Sigma Hydrids (HYD)  - 08:16 (124) +03    Velocity - 61km/sec.
Northern Hemisphere - <1 per hr. Southern Hemisphere - <1 per hr.

Psi Ursa Majorids (PSU)  - 11:19 (170) +43     Velocity - 61km/sec.
Northern Hemisphere - <1 per hr. Southern Hemisphere - <1 per hr.

Alpha Draconids (DAD)  - 13:34 (204) +60    Velocity - 44km/sec.
Northern Hemisphere - <1 per hr. Southern Hemisphere - <1 per hr.

*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