Meteor Activity Outlook for April 16-22, 2011
April 16, 2011
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.
Meteor activity picks up a bit during April as two major showers are active during the month. The first of these, the Lyrids, are active from the 16th through the 25th, with a pronounced maximum on the 22nd. The Eta Aquariids start appearing near the 28th and reach maximum activity during the first week in May. Sporadic rates are low but steady as seen from the mid-northern hemisphere (45 N). Sporadic rates seen from the mid-southern hemisphere (45 S) rise this month toward a maximum in July.
During this period the moon reaches its full phase on Monday April 18. At this time the moon will lie opposite the sun and will be in the sky all night long. This is the worst time of the month to try and view meteor activity as the bright moonlight will obscure all but the brightest meteors. The estimated total hourly rates for evening observers this week is near one as seen from the northern hemisphere and two as seen from the southern hemisphere. For morning observers the estimated total hourly rates should be near six from the northern hemisphere and seven as seen from south of the equator. 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 this week due to 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 April 16/17. These positions do not change greatly day to day so the listed coordinates may be used during this entire period.
The list below presents a condensed version of the expected activity this week. Rates and positions are exact for Saturday night/Sunday morning.
Shower Name RA DEC Vel Rates km/s NH SH PPU Pi Puppids 07h 06m -44 18 <1 <1 SLE Sigma Leonids 13h 18m +06 20 <1 <1 ANT Antihelions 14h 40m -15 30 1 1 LYR Lyrids 17h 56m +35 48 1 <1 ZCY Zeta Cygnids 20h 00m +37 42 <1 <1 RA - Right Ascension DEC - Declination Vel - Velocity relative to Earth (in km per sec) Rates - Rate of visible meteors per hour from a dark site NH - Northern Hemisphere SH - Southern Hemisphere