If, around August 12th, you go outside between midnight and dawn and look up for a minute or so, you’ll most likely spot a meteor streaking through the sky. The August Perseid meteors were the first that astronomers associated with a particular comet. In the mid 1860s, Italian astronomer Giovanni Schiaparelli observed that Perseids followed the appearance of the Swift-Tuttle Comet.
The Perseids are among the most reliable of the year’s cosmic fireworks displays. In mid-August, Earth passes through a stream of grit left behind by Comet Swift-Tuttle in its eccentric 130-year orbit. Flecks of debris burn up as they pass through the atmosphere, at a height of about 60 miles, producing streaks of light — and sometimes leaving behind glowing trails that fade into the night.
The Perseids are so called because the point they appear to come from, called the radiant, lies in the constellation Perseus. Meteor showers occur when Earth moves through a meteor stream. The stream in this case is called the Perseid cloud and it stretches along the orbit of the Comet Swift-Tuttle. The cloud consists of particles ejected by the comet as it passed by the Sun.
Most of the dust in the cloud today is approximately a thousand years old. However, there is also a relatively young filament of dust in the stream that boiled off the comet in 1862. The approximate rate of meteors originating from this filament is much higher than normal.
- Watch for Perseid meteors in the night skies from July 23rd to August 22nd.
- Get away from artificial light if possible.
- Dress appropriately for nighttime viewing. As a summer event, Perseids may be one of the few meteor showers you can observe in shirtsleeves.
- Look toward constellation Perseus for the radiant point of Perseid meteors. They’ll seem to come from that area, which is about halfway above the horizon in the northeast quadrant of the sky.
- Begin your search for Perseids after 10 p.m. (although the best viewing comes from midnight until dawn).
- Recline with your feet facing due south and look straight up. Perseids should appear to come from over your left shoulder.
The Perseid meteor shower peaks on the new-Moon night of Sunday–Monday, August 12–August 13 and can be seen from any place in the northern hemisphere. The Perseid meteors appear to stream away from their radiant near the border of Perseus and Cassiopeia.
The meteor rate, for an observer at a dark-sky site in the northern temperate latitudes, increases to roughly 30 per hour in the pre-dawn hours on Saturday, 45 per hour on Sunday morning, and 80 per hour before the sky starts to get light on Monday morning.