(meteorobs) Meteor Activity Outlook for May 5-11, 2012

[Robert Lunsford]

During this period the moon reaches its full phase on Sunday the May 6th. At this time the moon will be located opposite the sun and will be in the sky the entire night. These are the worst lunar conditions of the month but not necessarily the worst time to view meteor activity this month. This is due to the maximum of the strong Eta Aquariid shower, which is predicted to occur this week. Even though the moon will be bright, some activity from this shower can be seen during the last dark hour before dawn. Just how many can be seen will depend on your latitude and the transparency of your skies. Be certain to face toward the east with the moon at your back. Eta Aquariid meteors will shoot upward from the eastern horizon during the last hour before dawn. They are not visible prior to this time as the radiant does not clear the horizon until then. The estimated total hourly rates for evening observers this week is near two for observers in the northern hemisphere and three for those south of the equator. For morning observers the estimated total hourly rates should be near twelve as seen from mid-northern latitudes and twenty four from mid-southern latitudes. 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 the bright 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 May 5/6. 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. Viewing there 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.

The following showers are expected to be active this week. Detailed listings will be back next week when the lunar conditions are more favorable.
 
Antihelion (ANT) - 15:52 (238) -20   Velocity 30km/sec
Northern Hemisphere - 1 per hr Southern Hemisphere - 2 per hour

Eta Lyrids (ELY) - 19:24 (291) +43  Velocity 43km/sec
Northern Hemisphere - <1 per hr Southern Hemisphere - <1 per hour

Nu Cygnids (NCY) - 20:44 (336) +51   Velocity 42km/sec
Northern Hemisphere - <1 per hr Southern Hemisphere - <1 per hour

Eta Aquariids (ETA) - 22:36 (339) -01   Velocity 67km/sec
Northern Hemisphere - 5 per hr Southern Hemisphere - 10 per hour

Clear Skies!
Robert Lunsford
American Meteor Society