(meteorobs) Meteor Activity Outlook for August 13-19, 2011

Robert Lunsford lunro.imo.usa at cox.net
Fri Aug 12 18:00:46 EDT 2011

During this period the moon reaches its full phase on Saturday August 13th. At this time the moon will lie opposite the sun in the sky and will be above the horizon all night long.  Next week the waning gibbous moon will rise later and later in the evening sky and will allow some dark sky viewing for a short time after the end of evening twilight. The estimated total hourly rates for evening observers this week is near six 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 eighteen from mid-northern latitudes and eight 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 intense 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 August 13/14. 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 descriptions of each shower will be continued next week when the moon will not interfere as much.

August Draconids (AUG) - 18:06 (271) +62   Velocity - 23km/sec.
Northern Hemisphere - <1 per hr. Southern Hemisphere - <1 per hr.

Kappa Cygnids (KCG) - 19:04 (286) +51   Velocity - 23km/sec.
Northern Hemisphere - <1 per hr. Southern Hemisphere - <1 per hr.

Antihelion (ANT) -22:16 (334) -08   Velocity - 30km/sec.
Northern Hemisphere - <1 per hr. Southern Hemisphere - 1 per hr.

Delta Aquariids (SDA) - 23:33 (353) -12   Velocity - 42km/sec.
Northern Hemisphere - <1 per hr. Southern Hemisphere - 1 per hr.

Eridanids (ERI) - 03:09 (047) -09   Velocity - 64km/sec.
Northern Hemisphere - <1 per hr. Southern Hemisphere - <1 per hr.

Perseids (PER) - 03:18 (050) +58   Velocity - 61km/sec.
Northern Hemisphere - 10 per hr. Southern Hemisphere - 2 per hr.

Beta Perseids (BPE) - 03:22 (051) +37   Velocity - 67km/sec.
Northern Hemisphere - <1 per hr. Southern Hemisphere - <1 per hr.
Clear Skies!
Robert Lunsford
American Meteor Society

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