Meteor Activity Outlook for January 12-18, 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 wanes from a last quarter phase and will be a day before new at the end of the period. Some slight lunar interference will occur this weekend from the waning crescent moon but this can been easily overcome be viewing in a direction away from the moon. By early next week the moon will not be a factor at all. The estimated total hourly rates for evening observers this week is near four no matter your location. For morning observers the estimated total hourly rates should be near fifteen no matter your location. 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 listed below are exact for Saturday night/Sunday morning January 13/14. 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 08:24 (126) +17. This area of the sky lies in central Cancer near the dim star Theta Cancri. 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.

The Coma Berenicids (COM) peaked near December 20 with an average ZHR of five. Rates have now fallen to less than one per hour no matter your location. The current location of this radiant is 13:08 (197) +15. This area of the sky is located in eastern Coma Berenices just two degrees south of the fourth magnitude star Alpha Comae Berenices. 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.

Sporadic rates have passed the late year plateau for observers located in the northern hemisphere. One would expect to see perhaps fourteen random meteors during the last hour before dawn from rural observing sites. During the first dark hour after the end of evening twilight, perhaps four random meteors can be seen per hour. Sporadic rates increase as the night progresses so rates seen near midnight would be near nine per hour. Sporadic rates seen from the southern hemisphere are near the first of two annual maximums. One would expect to see approximately the same rates that are visible from the northern hemisphere.