(meteorobs) Meteor Activity Outlook for December 1-7, 2012

[Robert Lunsford]

No matter where you live, the first half of December provides some of the best meteor activity of the year. This activity will be tempered by a bright moon during the first week of the month. The next two weeks are moon-free and offer the meteor observer ample opportunities to view some celestial fireworks. 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. Much of the activity mentioned above can also be seen from the southern hemisphere. While the sporadic rates are not as strong as those seen from the north, they are stronger than the previous months and heading for a maximum in February. The warm, but short summer nights south of the equator make for some great viewing as long as the moon does not interfere.

During this period the moon reaches its last quarter phase on Thursday December 6th. At this time the moon is located ninety degrees west of the sun and rises near 2300 (11pm) local standard time (LST). This weekend the waning gibbous moon will rise during the early evening hours and will effectively spoil the sky the remainder of the night with its intense lunar glare. The estimated total hourly meteor rates for evening observers this week is near four for observers located at mid-northern latitudes and three for observers in mid-southern latitudes. For morning observers the estimated total hourly rates should be near twelve from the mid-northern hemisphere and seven from the mid-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. Rates are reduced during this period due to moonlight.

The radiant (the area of the sky where meteors appear to shoot from) positions and rates listed below are exact for Saturday night/Sunday morning December 1/2. 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.

Details of each active shower will return next week when the observing conditions improve.

The following radiants are expected to be active this week.  Rates and positions are exact for Saturday night/Sunday morning .

Dec. Phoenicids (PHO) - 01:00 (015) -53    Velocity - 18km/sec.
Northern Hemisphere - <1 per hr.    Southern Hemisphere - <1 per hr.

Andromedids (AND) - 01:28 (022) +55   Velocity - 19km/sec.
Northern Hemisphere - <1 per hr.   Southern Hemisphere - <1 per hr.

Northern Taurids (NTA) - 05:03 (076) +26   Velocity - 29km/sec.
Northern Hemisphere - 1 per hr.   Southern Hemisphere - <1 per hr.

November Orionids (NOO) - 06:10 (093) +15   Velocity - 44km/sec.
Northern Hemisphere - 2 per hr.   Southern Hemisphere - 1 per hr.

Geminids (GEM) - 06:47 (102) +34   Velocity - 35km/sec.
Northern Hemisphere - 1 per hr.   Southern Hemisphere - <1 per hr.

Puppid-Velids (PUP) - 08:00 (120) -45   Velocity - 40km/sec.
Northern Hemisphere - <1 per hr. Southern Hemisphere - 1 per hr.

Sigma Hydrids (HYD)  - 08:04 (121) +04   Velocity - 61km/sec.
Northern Hemisphere - 1 per hr. Southern Hemisphere - 1 per hr.

Dec. Kappa Draconids (DKD) - 12:17 (184) +71   Velocity - 43km/sec.
Northern Hemisphere -<1 per hr. Southern Hemisphere - <1 per hr.

Clear Skies!
Robert Lunsford
American Meteor Society