Meteor Activity Outlook for March 23-29, 2013
March 26, 2013
The following is a slightly edited version of Bob Lunsford’s excellent weekly summary of meteor activity. The original version can be found at the American Meteor Society’s site.
As seen from the northern hemisphere, March is the slowest month for meteor activity. No major annual showers are active and only a few very weak minor showers produce activity this month. The sporadic rates are also near their annual minimum so there is not much to look forward to this month except for the evening fireballs that seem to peak this time of year from the northern hemisphere. This could be due to the fact the Antapex radiant lies highest above the horizon this time of year during the evening hours. From the southern hemisphere, activity from the Centaurid complex begins to wane with only the weak activity visible from Norma and perhaps others areas nearby. At least southern sporadic rates are still strong to make the late summer viewing a bit more pleasurable.
During this period the moon reaches its full phase on Wednesday March 27th. At this time the moon is located opposite the sun and will be above the horizon the entire night. This weekend the waxing gibbous moon will set during the late morning hours, allowing a short period of dark skies between moon set and the start of morning twilight. The estimated total hourly meteor rates for evening observers this week is near two as seen from the northern hemisphere and three as seen from south of the equator. For morning observers the estimated total hourly rates should be near five 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 interfering 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 March 23/24. These positions do not change greatly day to day so the listed coordinates may be used during this entire period.
The following showers are expected to be active this week:
The large Anthelion (ANT) radiant is currently located at 13:04 (196) -07. This position lies in central Virgo, five degrees northwest of the first magnitude star Spica (Alpha Virginis). These meteors may be seen all night long but the radiant is best placed near 0200 Local Daylight Time (LDT) when it lies on the meridian and is 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 slow velocity.
IMO #49 is an unnamed shower active between March 22 and April 7. The radiant is currently located at 19:28 (292) +42. This position lies on the Lyra-Cygnus border, directly between the bright stars Vega and Deneb. Rates are expected to be exceedingly low this week no matter your location. Your best chance to catch this activity would be near April 3rd when it briefly becomes the strongest radiant in the sky. The radiant is best placed in a dark sky just before dawn. At 45km/sec. this shower would produce meteors of medium velocity.
As seen from the mid-northern hemisphere (45N) one would expect to see approximately three sporadic meteors per hour during the last hour before dawn as seen from rural observing sites. Evening rates would be near one per hour. As seen from the mid-southern hemisphere (45S), morning rates would be near five per hour as seen from rural observing sites and two per hour during the evening hours. Locations between these two extremes would see activity between the listed figures. Rates are reduced during this period due to moonlight.
The list below presents a condensed version of the expected activity this week.
Rates and positions are exact for Saturday night/Sunday morning .
Anthelions (ANT) – 113:04 (196) -07 Velocity – 30km/sec.
Northern Hemisphere – 2 per hr. Southern Hemisphere – 2 per hr
IMO #49 – 19:28 (292) +42 Velocity – 45km/sec.
Northern Hemisphere – <1 per hr. Southern Hemisphere – <1 per hr
American Meteor Society