Leonid Meteors in 2015: Modest but Moonless

This year's Leonid meteor shower, which peaks tonight, will offer modest numbers of "shooting stars" — but might reward you with some dazzling fireballs.

Leonid fireball from 2001

A spectacular Leonid fireball photographed during the meteor storm on November 18, 2001.
© John Pane

Anyone who watched for the annual Leonid meteors in 1998 and 1999 will never forget the hundreds and thousands of bright streaks that seared the late-night sky. This intense cascade resulted because the particles' source, Comet 55P/Tempel-Tuttle, was coursing through the inner solar system during its 33-year-long orbit.

Most years, however, the Leonids provide a much more modest, delivering 10 to 15 meteors per hour during its relatively brief peak. That's going to be the case again in 2015. While the numbers might be modest, the timing of "traditional," most reliable part of the shower (around 5h Universal Time on the 18th) corresponds to very late evening tonight and the predawn hours of Wednesday morning for observers on the U.S. East Coast.

According to meteor researcher Mikhail Maslov, there might be more than one peak tonight, with a second pulse of meteors occurring today around 21h UT. That favors observers in Asia — it's still daylight in North America.

But the Leonids have surprised the theorists before, and they surely will again. So if your sky is clear, stay up late to try to spot them. Fortunately, moonlight won't be a problem. The shower's radiant, near the Sickle asterism in the head of Leo, the Lion, rises in the northeast between 11 p.m. and midnight, by which time the Moon (not quite at first quarter) will have set. The number of meteors you'll see increases steadily as Leo rises in the sky, getting its highest just as the predawn sky is starting to get light.

Sky & Telescope diagram

The direction to watch is wherever your sky is darkest. Notice the meteors' flight paths; only those streaking away from the direction to the constellation Leo are Leonids. They're incredibly fast-movers as meteors go, striking Earth's atmosphere at 71 km per second (160,000 mph). Sometimes they create dazzling fireballs with an afterglow (technically known as a train) that can linger as a ghostly thread in the sky for up to a minute.

Another, less-known meteor shower is going on simultaneously — the Taurids. They're sparse but tend to be very bright and much slower. And you're bound to see a few sporadics that aren't associated with any major shower.

Be sure to bundle up warmly; meteor-watching is always colder than you expect. Ideal meteor-watching equipment is a comfortable lounge chair, a warm sleeping bag, and a pillow. If you live in a city or suburb, consider traveling to a dark location far from city skyglow. In any case, find a spot where no lights glare directly into your eyes.

For more information, read our article Basics of Meteor Observing. And you can also download our free eBook on meteor observing.

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