Whenever you're out astronomizing during this time of year, you're likely to notice an occasional meteor that streaks away from the direction of the constellation Perseus, which is rising in the northeast during late evening. Those streaks are the calling cards of the annual Perseid meteor shower.The Perseids are at least a little active throughout early and mid-August, and in fact we received reports that the shower was under way by August 5th or 6th.
But the night or two around the shower's maximum are what bring out the crowds. This year the Perseids should peak on the morning of August 12th, around 11h to 14h Universal Time. That's 4 to 7 a.m. Pacific Daylight Time, good timing for North America and especially the Far West. But wherever you're located, from midnight to dawn is the best time to watch.
Clear and dark skies permitting, you should be able to spot lots of Perseids this year — but only if you dodge the light of the waxing gibbous Moon. The Moon hangs around until as late as 1 or 2 a.m. daylight saving time on the morning of the 12th, depending on where you live in your time zone. But after that, you get nearly three hours of darkness before the first stealthy glimmer of dawn. The Moon sets earlier by nearly an hour per day on preceding nights, and about an hour later each night thereafter.
(To find your local times of moonset and the start of dawn, put your location and time zone into our online almanac. If you're on daylight saving time like most of North America, make sure the Daylight Saving Time box is checked.)Fortunately, the brightest meteors will show right through the moonlight. But before 11 p.m. or midnight, there won't be as many of them in any case. Early morning your time is when your side of Earth faces most directly into oncoming meteors — Perseids included.
Find a spot with an open view of the sky, wrap up warmly in winter clothes and a sleeping bag (it gets cold under a clear sky late at night!), and don't forget the mosquito repellent. If you have a good, dark sky, you may see a meteor zipping into the upper atmosphere about once per minute on average.
Perseids can flash into view anywhere in the sky, so watch whatever part of your sky is darkest. But all of them, if you trace their paths far enough backward, appear to be radiating from a point in northern Perseus below Cassiopeia.
You won't need any kind of optical aid to enjoy the Perseids — it's a wonderful opportunity for "eyeball astronomy." Some observers like to keep a careful meteor count. If you do this by certain standardized methods, you can report your count to the International Meteor Organization or the North American Meteor Network to help track the shower's behavior from year to year. If that interests you, read more.
You may also see occasional meteors from two lesser showers that are active at the same time: the Delta Aquarids and Kappa Cygnids. These meteors move noticeably slower than Perseids. And then there are that sporadics, members of no organized shower at all, that occasionally punctuate the night.
Good luck! And use the comment section below to let me know how the Perseids looked from your location.
While you're watching for Perseids on the morning of the 12th, keep an eye on Algol, Beta Persei. This famous eclipsing binary star should be at minimum light, magnitude 3.4 instead of its usual 2.1, from about 2 to 4 a.m. Tuesday morning Eastern Daylight Time (6:00 to 8:00 Universal Time). Algol takes several additional hours to fade and to rebrighten. Here's a naked-eye comparison-star chart.