Meteor Activity Outlook for April 7-13, 2006

With the arrival of April, observers in the northern hemisphere still suffer with low sporadic rates, especially during the evening hours. Observers south of the equator will witness increasing sporadic rates with the maximum activity occurring in July. The overall meteor activity is better than March due to the activity of the two major showers; the Lyrids and the Eta Aquarids. The Eclipticid radiant begins the month in the constellation of Virgo. By the 15th, the Virginid portion of the eclipticid activity becomes quite low and few meteors are seen. During the last week of the month a strong center of eclipticid activity becomes active in the constellation of Libra. Many of these meteors can be noticed while viewing early Eta Aquarid activity. Due to the southerly position of the Eclipticids this time of year, they are slightly better seen south of the equator. The most favorable time to view meteor activity this month would be near the new moon, which occurs on April 27. April is also prime time for viewing fireballs. No exact radiant has been determined for these fireballs but a good number of them are associated with the Eclipticid radiant. Therefore the hours near 0200 (local daylight saving time) are the most favorable time to view these events. Still, many have been witnessed during the early evening hours, when the radiant area lies low in the southeastern sky.

The moon reaches its full phase on Thursday April 13. At that time the moon will be rise as the sun sets and set as the sun rises. This weekend the waxing gibbous moon sets during the early morning hours allowing a window of opportunity to view under dark conditions. This window will shrink as the week progresses. The estimated total hourly rates for evening observers this week is near one for observers in the northern hemisphere and two for those south of the equator. For morning observers the estimated total hourly rates should be near seven for those located in the Northern Hemisphere and ten for those 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 due to moonlight.

The radiant positions listed below are exact for Saturday night/Sunday morning April 8/9. 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 Eclipticid (ECL) radiant is now centered at 13:28 (202) -07. This area of the sky is located in central Virgo, four degrees north of the first magnitude star Spica (Alpha Virginis). This radiant is best placed near 0200 local daylight time when it lies on the meridian and is highest in the sky. Rates should be near one per hour for those north of the equator and two per hour south of the equator. 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).

The Delta Pavonids (DPA) are an obscure shower listed among the radiants of the Dutch Meteor Society. They list the ZHR’s as five but recent observations fail to show much activity at all. The predicted date of maximum activity was March 28. Current rates would most certainly be less than one per hour. The radiant currently lies at 22:28 (337) -67. This area of the sky is located near the fourth magnitude star Delta Tucanae. This area of the sky is too far south to be seen north of the northern equatorial areas. Only observers living in far southern locations such as Australia, South Africa, and southern South America have any chance of seeing activity from this radiant. The best time to view possible activity is just before the start of morning twilight, when the radiant lies highest in a dark sky. With an entry velocity of 60 kilometers per second, a majority of these meteors will appear to move swiftly.

The Sporadic rates for the Northern Hemisphere are now nearing their annual minimum activity. 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 one random meteor can be seen per hour. Sporadic rates seen from the southern hemisphere are now increasing toward a secondary maximum in July. One would see approximately eight random meteors per hour during the late morning hours and two per hour during the evening. Evening rates from all areas are reduced due to moonlight.

Clear Skies!