The Perseid meteor shower, an annual celestial event beloved by millions of skywatchers around the world, is returning to the night sky for 2014. But this year it will compete with bright moonlight for visibility.
Sky & Telescope magazine predicts that the Perseid shower will be at or near its peak late on Tuesday night, August 12-13 (from late Tuesday evening until dawn Wednesday). “But this year the Moon will be just two days past full on the peak night, so moonlight will fill the sky,” says Alan MacRobert, a senior editor at Sky & Telescope. “The moonlight will hide many of the fainter meteors. The brightest ones, though, will still shine through.”
A recent NASA analysis of all-sky images taken from 2008 to 2013 shows that the Perseids deliver more bright meteors (those that outshine any star) than any other annual meteor shower.
An occasional Perseid may catch your attention early in the evening, but the prime viewing hours are from about 11 p.m. or midnight (local time) until the first light of dawn. This is when the shower’s “radiant,” its perspective point of origin, is high up in your sky. The higher the radiant, the more meteors streak into the Earth’s upper atmosphere all over the sky.
To enjoy the Perseids, you need no equipment but your eyes. Find a dark spot with a wide-open view overhead. Bring a reclining lawn chair or a ground cloth so you can lie back and watch the sky in comfort. Bundle up in blankets or a sleeping bag, both for mosquito shielding and for warmth; clear nights can grow surprisingly chilly under the open stars (due to radiational cooling).
Face away from the Moon. “Relax, be patient, and let your eyes adapt to the dark,” says MacRobert. “Even with the moonlight, you’ll probably see a ‘shooting star’ at least every five minutes or so on average.”
When you see a meteor, track its path backward. If you eventually come to the constellation Perseus — which climbs the northeastern sky as the night progresses — then a Perseid is what you’ve just witnessed.
Occasionally you may spot an interloper. The weaker Delta Aquariid and Kappa Cygnid showers are also active during Perseid season, and there are always a few random, “sporadic” meteors. All of these track back to other parts of the sky.
How and Why
Meteors are caused by tiny, sand- to pea-size bits of dusty debris streaking into the top of Earth’s atmosphere about 80 miles up. Each Perseid particle zips in at 37 miles (60 km) per second, creating a quick, white-hot streak of superheated air. Grape Nuts cereal nuggets are a close match to the estimated size, color, and texture of typical meteor-shower particles.
These particular bits were shed long ago by Comet Swift-Tuttle. They are now distributed all along the comet’s orbit around the Sun. Earth passes through this tenuous “river of rubble” every year in mid-August.
More about the Perseids and how to watch them appears in the August issue of Sky & Telescope magazine and at SkyandTelescope.com/ Contacts:
Alan MacRobert
Senior Editor, Sky & Telescope
+1 617-864-7360 x2151
amacrobert@SkyandTelescope.com
Kelly Beatty
Senior Contributing Editor, Sky & Telescope
+1 617-416-9991
jkellybeatty@comcast.net
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