Not all summer fireworks are of earthly manufacture, the Perseid meteor shower being a notable case in point. On the morning of August 12th (that is, the morning after Aug. 11th, before sunrise) the Perseid meteor shower reaches its peak of activity as the Earth travels through the densest part of the debris stream left by the long-period comet 109P Swift-Tuttle.

A bright moon can do a first-rate job in washing out a meteor shower; fortunately, the moon sets at 1:17am on the morning of August 12, just as the constellation Perseus (from which the meteors appear to radiate) is climbing high into the northeastern sky, as viewed from here in the Pacific Northwest.

The following graphic, looking northeast at the moment of moonset, 1:17am on the morning of Aug. 12th, shows the outlines of the constellation of Perseus and the location of the meteor radiant. The average number of meteors per hour is from 50-80, but it is important to keep in mind that the meteors can appear anywhere in the sky. Their association with the shower is apparent because their paths recorded onto a star chart trace back to the radiant point in the constellation of Perseus, like the spokes of a wheel.

Since Perseus rises higher and higher into the sky as the morning progresses, viewing the shower can make for a stiff neck. The ideal lawn furniture for viewing a meteor shower is a chaise lounge. Barring that, a blanket on the grass and a pillow for your head will suffice.

And, yes, I am aware that the morning of the 12th is a Tuesday. C’est la vie on Planet Earth; nature won’t reschedule. For what it’s worth, however, during the period from August 8-14 there are still Perseids to be seen - just not quite so many as on maximum. Who knows - you might even see a fireball on any of these nights (barring cloud cover), like the one pictured at the beginning of this post.

How fast is a Perseid meteor traveling when it enters the Earth’s atmosphere? Anywhere from 80,000 to 130,000 miles per hour.

For more information:

• American Meteor Society
• NASA Perseids 2008 Page
• Time Lapse Movie of the Perseid Meteor Shower