Meteor Activity Outlook for February 8-15, 2007

February meteor rates will be less than those seen in January for observers located in the northern hemisphere. Only the weak Delta Leonids are active this month. Combine this with falling sporadic rates and it is often a struggle to go out into the cold. The southern hemisphere also experiences a dip in sporadic rates but the activity from the Alpha Centaurids more than makes up this difference. Observers south of the equator are encouraged to take advantage of the warm nights and to view the meteor activity as often as possible. There are many suspected radiants in the southern sky this time of year which are in need of study. Only the Alpha Centaurids have been verified but there may be other centers of activity awaiting discovery.

This week the moon reaches its last quarter phase on Saturday February 10. At this time the moon will rise near midnight local standard time and will cause minor interference the remainder of the night. With each passing night the moon will become less of a nuisance as its phase wanes and it rises later in the morning hours. The estimated total hourly rates for evening observers this week is near two for those viewing from the northern hemisphere and three for those located south of the equator. For morning observers the estimated total hourly rates should be near nine for observers north of the equator and fourteen for those observers viewing from the southern hemisphere. 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. Morning rates are reduced due to moonlight.

The radiant positions listed below are exact for Saturday night/Sunday morning February 10/11. 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 10:20 (155) +09. This area of the sky lies in southern Leo, three degrees southeast of the first magnitude star Regulus (Alpha Leonis). This radiant is best placed near 0100 local standard time when it lies on the meridian and is situated highest in the sky. Rates at this time should be near two per hour no matter your location. With an entry velocity of 30 km/sec., the average Antihelion meteor would be of medium-slow speed.

The Alpha Centaurids (ACE) reach maximum activity on February 8 with a ZHR near five. This radiant is now centered at 14:24 (216) -60. This area of the sky lies in southeastern Centaurus, directly between the brilliant stars Rigel Kentaurus (Alpha Centauri) and Hadar (Beta Centauri). This radiant is best placed near 0500 local standard time when it lies on the meridian and is situated highest in the sky. Unfortunately for northern observers, this radiant does not rise above the horizon for observers north of latitude 30 north. Therefore only the north tropical areas and points further south can view this activity. With an entry velocity of 56 km/sec., the average Alpha Centaurid meteor would be of swift speed.

Sporadic rates are slowing decreasing for observers located in the northern hemisphere. One would expect to see perhaps seven random meteors during the last hour before dawn from rural observing sites. During the first dark hour after the end of evening twilight, perhaps two 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 are near the first of two annual maximums. One would expect to see perhaps nine 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, increasing to six by midnight. Morning rates are reduced due to moonlight.