A STARRY SIGHT, IF THE WEATHER CLEARS.(MAIN)

Byline: DAN VERGANO USA Today

Wishing on a star? You may be in luck, weather permitting. Tonight's Leonid meteor storm will offer one of nature's best light shows this century.

The annual shower of shooting stars comes with a first storm peaking at about 11 p.m., visible in and around New England, and a second peak coming 6 hours later, visible nationwide.

Locally, seeing the shower may be difficult because of cloud cover.

``There may be a few holes in the clouds but don't get too hopeful,'' said National Weather Service Meteorologist Bob Kilpatrick, adding that tonight's forecast calls for partly cloudy skies.

``It's not going to be nice and wide open ... or overcast. It'll be somewhere in between.''

Although the Leonids seem to be coming from the constellation Leo the Lion (hence their name), in fact they derive from leftover comet dust. As Earth circles into sandy grains left in the tail of the comet Tempel-Tuttle, the dust particles hit our atmosphere at 158,440 mph and turn white-hot, lighting up as they pass through the air to form shooting stars. The grains are about 30 microns wide, a little over a thousandth of an inch, less than the width of a human hair.

The Tempel-Tuttle comet follows a 33-year circuit around the sun, zooming from the depths of Saturn's orbit to near Earth on an elongated trajectory.

Seeded by Tempel-Tuttle's 1767 and 1866 passes by the sun, this year's Leonids will end a string of impressive showers in recent years. The annual show will continue, but the comet, tugged out of position by Jupiter in 2029, will not reseed Earth's region of space with buckets of comet dust until 2098, said Alan MacRobert, senior editor at Sky & Telescope magazine. Until 2131, when that dust smacks into our atmosphere, the annual Leonids will be less impressive affairs -- a few hundred meteors per hour instead of the 5,000 to 6,000 per hour predicted for tonight.

Despite the shiny moon, ``we should still see lots of the bright ones,'' MacRobert said. The bulk of the storms are expected to last about two hours, with intense peaks in the middle. Visible only in the East, the first storm should produce ``Earth-grazers'' that skim the atmosphere, producing longer, reddish tails. The second should be more impressive, producing thousands of very bright meteors.

In the last few years, astronomers at NASA's Jet Propulsion Laboratory and the Minor Planet Center in Cambridge, Mass., have greatly increased their ability to correctly predict meteor storms based on the paths of past comets. Ribbons of dust millions of miles long linger after the passage of a comet, we now know. ``They made a believer out of me last year,'' said David Batch, head of the Abrams Planetarium at Michigan State University. His advice for sky watchers:

Dress warmly and bring a blanket. ``It's always colder than you think.''

Head someplace dark; bring a reclining lawn chair for a broad sky view.

Keep the moon out of your field of view so your eyes adjust to the dark.

Check the weather. Haze or clouds mean you're better off sleeping in.

Also remember your friends and loved ones before getting transfixed by the spectacle. ``Last year, I was supposed to wake my wife up for the storm and I only remembered a minute before the sky clouded over,'' Batch said. ``We're hoping I get to redeem myself this year.''

Last year's Leonids filled the sky with about 1,000 meteors an hour and three years ago over Europe they fell at a rate of 3,000 per hour.