posted 08-09-2002 12:26 PM            

The thin crescent Moon sets early on the evening of August 12th, leaving the sky fully dark for this year’s Perseid meteor shower. The display should peak later that night for observers throughout the Northern Hemisphere, especially as morning twilight begins. That’s when the radiant (the patch of sky between Perseus and Cassiopeia from which the Perseids appear to come) is highest in midnorthern latitudes. Skywatchers can expect to see 60 or more Perseids per hour, provided the sky is very clear and dark.
If you miss the Perseids that night, all is not lost. The shower lasts for two weeks or so, with excellent rates in the predawn hours of August 10th through 15th. Far fewer meteors will appear before midnight, even on the night of the shower’s maximum, because the radiant is then quite low in the sky. The radiant is always low or below the horizon for countries like Australia, New Zealand, and South Africa, where few, if any, Perseids can be seen.

The 1992 return of Comet Swift-Tuttle, parent comet of the Perseids, brought with it a “new peak” that was superimposed on the shallower, traditional Perseid maximum. By 1999, however, the new peak had greatly subsided (Sky & Telescope: August 2001, page 108), and it's completely missing from analyses of the 2000 and 2001 Perseids by the International Meteor Organization. So the forecast for 2002 reads much as it would have in the 1980s: the Perseids should peak for 12 hours or more, centered on the time when the Sun’s ecliptic longitude is 140.0° (equinox 2000.0). That translates to 22h Universal Time on August 12th this year. European observers are optimally positioned for the Perseid peak, but North Americans aren't far behind.

The Perseid meteor shower radiant (the apparent point of origin of the meteors) is located part way up the sky in the NNE at 11 p.m. in mid-August. S&T: Gregg Dinderman.




Simply counting meteors is one good way for amateurs to contribute to meteor science. The techniques are explained in the meteor section of this Web site. But the Perseids are a reliable shower, rich in bright meteors with long-lasting trains, and skywatchers may find other projects almost irresistible.