Meteor Activity Outlook for August 24-30, 2007

August is the best month for viewing meteor activity from the northern hemisphere. Not only is the activity enjoyable but the balmy nights are much more pleasant than those experienced later in the year. As the month begins the southern radiants are still active and often matching the sporadic rates. The sporadic rates increase as the month progresses providing a decent show for the normally slow evening hours. The Perseids kick into high gear the second week of the month and fill the skies with colorful streaks of light during the entire night. From the southern hemisphere activity falls precipitously. This is much like what the northern hemisphere experiences moving from January into February. The southern radiants put on a good show the first week of the month. They taper off the second week and are nearly extinct by the third. In the meantime the sporadic rates that were so impressive in early July are now half as strong and still getting weaker. Unless you are located near the equator you will not see much of the Perseids. From the southern hemisphere any evening Perseids are impossible to see. You have to wait until the last hours before dawn and hope that some will shoot upwards from low in the northern sky.

During this period the moon reaches its full phase on Tuesday August 28. The moon will remain a major factor during this entire period obscuring all but the brightest meteors. The sources of meteors listed below are active during this period but will be difficult to observe this week due to the lunar glare. If your sky is transparent and the limiting magnitude exceeds +5.0, then you may be able to achieve some success. The estimated total hourly rates for evening observers this week is two from the northern hemisphere and one from south of the equator. For morning observers the estimated total hourly rates should be near seven from the northern hemisphere and four from 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. Rates are reduced this week due to intense moonlight.

The radiant positions listed below are exact for Saturday night/Sunday morning August 25/26. 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. Taking this advice this 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 full descriptions of each active meteor shower will continue next week when the moon becomes less of a nuisance to observers.