The Perseid Meteor Shower of August

As I write this column in mid-July, it appears we may have finally moved into a more favorable weather pattern that will allow us stargazers to view the starry heavens once again. Though I am reluctant to even mention the word “shower,” the upcoming shower of meteors in August is the annual Perseids.

Each year centered on August 12, the Earth passes through a couple of streams of particles stripped off Comet 109P/Swift-Tuttle and deposited in orbit about the Sun. At this point in time and space the density of the stream is a little thin, but the resulting display of shooting stars is still worth watching as the meteors plunge into our atmosphere at many miles per second and disintegrate.

Though perhaps the night of August 12-13 will hold the best prospects for observing as many shooting stars as possible, I would also suggest you observe on the previous night as well. Why? The peak of activity is predicted to occur during daylight hours on the 12th. In either case, the Perseids perform best from midnight until dawn’s early light. However, the almost last quarter Moon will rise before midnight, so its bright presence will somewhat diminish the number of meteors that can be seen.

Maximize your chances of observing as many meteors as possible by selecting a location well away from light pollution and get comfortable on a lounge chair or in sleeping bag. Try to block out the Moon with a nearby building so its light will not shine directly in your eyes. And this year, exercise special caution and keep the mosquitoes at bay.

The Perseids appear to radiate from an area of sky, called the radiant point, in the constellation Perseus. Perseus is well up in the northeast sky after midnight. Face this general direction when you first begin your observing session and gradually follow the radiant across the sky. As Perseus rises higher into the sky, the number of meteors will increase as the morning progresses.

The Perseids are usually green, red or orange in color and blaze across the heavens at 134,222 miles per hour. And some members of this shower are bright and often produce exploding fireballs. Taking into consideration all the observing conditions for the Perseids this year, potentially one may expect to see 30 to 40 meteors per hour. But like the weather, anything is possible.

So if the weather does cooperate, spend a few hours outdoors on the mornings of August 11-12 and 12-13 to watch a beautiful display of shooting stars light up the sky. You never know when the “other” type of shower will prevent further astronomical adventures.

When it is clear on a Saturday night, don’t forget to visit Seagrave Memorial Observatory (http:/www.theskyscrapers.org) on Peeptoad Road in North Scituate for a tour of the heavens through our many telescopes. Or, on every clear Tuesday night please visit Ladd Observatory (http://www.brown.edu/Departments/Physics/Ladd/) in Providence. Check out their websites for the public night schedules.