Meteor Activity Outlook for March 3-9, 2006

With the arrival of March, we reach the nadir of meteor activity for the year. No matter your location, March has the lowest mean meteor rates of any month of the year. The only reasonable activity is produced by the Eclipticid radaint, now located in Virgo. Even this activity is only 2-3 shower members at best. At least this is one of the prime times for fireballs. From February through April, fireballs are frequently reported during the evening hours.

The moon reaches its first quarter phase on Monday March 6. At this time the moon will set near midnight, allowing the more active morning hours to be free of moonlight. The estimated total hourly rates for evening observers this week should be near two no matter your location. For morning observers the estimated total hourly rates should be near eight for Northern Hemisphere observers and ten for those located in 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. Evening rates are reduced slightly due to moonlight.

The radiant positions listed below are exact for Saturday night/Sunday morning March 4/5. 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. 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 radiants are active this week:

The Delta Leonids (DLE) peaked on February 24 with a ZHR of two. Current rates should be less than one per hour no matter your location. The radiant is located at 11:40 (175) +14. This area of the sky is located in eastern Leo, three degrees southwest of the second magnitude star Denebola (Beta Leonis). This radiant lies fairly close to the Eclipticid radiant so care must be taken when tracing activity back to this portion of the sky. The best time to view this activity is near 0100 local time, when the radiant lies on the meridian and at its highest point above the horizon. With an entry velocity of 23 kilometers per second, these meteors will appear to move slowly.

The Eclipticid (ECL)radiant is now centered at 12:08 (182) +01. This area of the sky is located in central Virgo, directly between the fourth magnitude stars Eta and Beta Virginis. This radiant is best placed near 0100 local standard time when it lies on the meridian and is highest in the sky. Rates should be near two per hour no matter your location. With an entry velocity of 30 km/sec., the average Eclipticid meteor would be of medium-slow speed. This radiant is a good source of fireballs now through the end of April. Those who send reports to the I.M.O. should label these meteors as Virginids (VIR).

Activity from the Theta Centaurids (TCE) is nearly over for this year. Rates are now well below one per hour and the shower activity will cease by mid-month. The radiant lies at 15:24 (231) -49. This position lies on the Lupus/Norma border, five degrees south of the the third magnitude star Epsilon Lupi. This area of the sky is best placed near 0400 local standard time when it lies highest in the sky. At 60 km/sec. the Theta Centaurids produce meteors of swift velocity.

The Gamma Normids (GNO) are active from a radiant located at 15:56 (239) -51. This position lies in central Norma, ten degrees west of the fourth magnitude star Gamma Normae. Average ZHR’s are near six at maximum (March 13). Current rates would be near two from the Southern Hemisphere and less than one north of the equator. Due to the far southern declination of the radiant, this shower is not well seen north of the northern equatorial regions. This area of the sky is best placed near 0500 local standard time when it lies highest in the sky. At 56 km/sec. the Gamma Normids normally produce meteors of swift angular velocities.

The Sporadic rates for the Northern Hemisphere are now well past their annual peak. One would expect to see perhaps six random meteors per hour during the last hours before dawn from rural observing sites. During the evening hours perhaps two random meteors can be seen per hour. Sporadic rates seen from the Southern Hemisphere are also decreasing toward a secondary minimum in March. One would see approximately six random meteors per hour during the late morning hours and two per hour during the evening. Evening rates are slightly reduced due to moonlight.