Meteor Activity Outlook for September 5-11, 2009

September offers longer nights and cooler temperatures in the northern hemisphere. In the sky, no major showers are visible from either hemisphere but the northern hemisphere enjoys the advantage of higher sporadic rates. The two recognized minor showers active in early September have high northern declinations (celestial latitude) therefore are much better suited to be viewed from locations north of the equator. During the second half of the month the antihelion radiant becomes entangled with the two Taurid radiants and it is impossible to separate them. Therefore the antihelion radiant will be excluded from the list from the second half of September until the end of the Taurid activity period late in November. Observers in the southern hemisphere suffer from some of their lowest rates of the year this month. The Taurid radiants are not too badly placed so observers south of the equator can expect to see a little of this activity toward the end of the month.

During this period the moon wanes from its full phase to nearly half illuminated by the 11th. This weekend the nearly full moon will be in the sky the entire night, making meteor observing difficult at best. As the week progresses the moon will rise later in the evening with each passing night but will still interfere with the prime morning observing hours. The estimated total hourly rates for evening observers this week is near four as seen from the northern hemisphere and one from the southern hemisphere. For morning observers the estimated total hourly rates should be near six from the northern hemisphere and two as seen from the southern hemisphere. 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. Meteor rates are greatly reduced by moonlight all this week.

The radiant positions and rates listed below are exact for Saturday night/Sunday morning September 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 full descriptions of each active meteor shower will continue next week when the moon becomes less of a nuisance to observers.

The table below presents a condensed version of the expected activity this week. Rates and positions are exact for Saturday night/Sunday morning.