Catch the End of the Perseids

Perseid meteor in Taurus
A bright Perseid flashed across the horns of Taurus before dawn on August 13, 2002, while Vincent Varnas was photographing from Stevenson, Washington. He used a 35-mm f/2 lens and Fujicolor Press 1600 film for this lucky 20-second exposure, one of many he took during 2½ hours of sky shooting. To the meteor’s lower left is Mars; to its right are Aldebaran and the Hyades, with the Pleiades above.
As expected, the annual Perseid meteor shower put on a nice display on its predicted peak night, August 11–12. Late-night skywatchers under dark skies typically reported seeing about a meteor a minute on average, normal for this shower.

In addition, reports Rainer Arlt of the International Meteor Organization (IMO), the prediction of a new, additional peak near 21:00 Universal Time August 11th this year "was confirmed by visual observations sent to the IMO. Particle simulations predicted that this peak is caused by material ejected from Comet Swift-Tuttle at its perihelion passage in 1862." Watch Sky & Telescope for a full report.

And the show isn't over yet. The Perseids should taper off during the next few nights, so it's not too late to catch at least some of them. For one or two nights after the peak, rates are roughly a quarter to half of the maximum. In fact, in some years the last stragglers have been recorded as late as August 24th.

Also, the Moon is now almost completely gone from the early-morning sky.

Meteor Basics

The Perseids are one of the two strongest and most dependable annual meteor showers (the Geminids of December are the other).
The meteoroids of the Perseid stream range in size from pebbles to sand grains and have a consistency like bits of ash. They ram into our upper atmosphere at a speed of 60 kilometers per second (37 miles per second), creating incandescent trails of shocked, ionized air as they vaporize.

Shower members appear to diverge from a patch of sky between Perseus and Cassiopeia. Their apparent divergence from this radiant point is an effect of perspective; the meteoroids are actually traveling in parallel through space. Meteors appearing near the radiant will appear short because we see them nearly end on, while those far from the radiant, seen broadside, look much longer.

In the early-evening hours the radiant is low in the north-northeast, so the meteors strike the upper atmosphere at a low angle — and therefore we see comparatively few of them per square kilometer at the atmosphere’s top. As the night advances, the radiant rises higher in the northeast, the meteors arrive more nearly straight down, and so we see greater numbers of them. By the time morning twilight begins, the radiant has climbed to around 60° altitude for observers at midnorthern latitudes.

Meteor watching is simple. Pick an observing site that’s free of glary lights nearby, has an open view of the sky, and preferably is as far as possible out from under city light pollution. Don’t forget the mosquito repellent. Bundle up in blankets or a sleeping bag, lie back, and gaze into the stars. The direction to watch is wherever your sky is darkest, usually straight up. For more observing hints, see "Basics of Meteor Observing".

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