The dim, obscure periodic comet 209P/LINEAR is about to pass close by Earth — and bring with it a trail of debris that could make for an exciting meteor shower during the predawn hours of Saturday May 24th for North America.

Update, morning of May 24th: Meteor watchers across North America who went out in the early morning hours report seeing few if any Camelopardalids. There was just a bit of shower activity, with only a handful of meteors seen per hour coming from the new radiant at best. For more details, see our first reports from amateur and professional observers.

Most skygazers are familiar with the usual "biggies" among meteor showers, such as the Perseids and Geminids. But if the calculations of celestial dynamicists are correct, we could experience a terrific meteor shower that virtually no one's ever heard of: the Camelopardalids.

Don't blame yourself for not knowing about this one — historic records show little evidence that the "Cams" have ever made an appearance before. They are bits of dust cast off from periodic comet 209P/LINEAR, an obscure, dim comet that orbits the Sun every 5.1 years. It's much too faint for naked-eye visibility (13th magnitude as of May 22nd).

What's got dynamicists excited, however, is that Earth might might pass right through relatively dense streams of debris shed by the comet long ago. This could create a strong burst of "shooting stars" on May 24th.

Several predictions suggest that you might see anywhere from 100 to 200 meteors per hour from a dark location free of light pollution. That would mean a couple per minute on average. Some (but not all) dynamicists think there's even an outside chance that the celestial spectacle could briefly become a meteor "storm," with more than 1,000 visible per hour! But it's also possible that the display might be weak, with just a few dozen meteors or fewer per hour even in a dark sky.

In any case, a high proportion of the meteors may be bright. And compared to other meteors, the Camelopardalids will move across the sky relatively slowly.

Timing is Right for North America

Storm or no storm, predictions agree that the peak will likely occur between about 6:30 and 7:30 Universal Time on the 24th. This timing favors North Americas, though it means you'll have to be out around 3 a.m. Eastern Daylight Time; midnight Pacific Daylight Time. The outburst will be brief, lasting just an hour or two, though a somewhat longer duration is possible. Moonlight from a slender waning crescent won't be a problem.

The rest of the world will miss out; all other land areas are either in daylight or on the side of the globe facing away from the incoming meteors.

The meteors will appear all over the sky, so you'll want to look in whatever direction gives you the darkest view. But if you trace their bright paths backward far enough, and they'll lead you to a location in the northern sky in the dim constellation Camelopardalis, the Giraffe, about 12° from Polaris.

Interestingly, in the past week there've been a few reports of really bright fireballs from this radiant direction. Are these early arrivals from the Camelopardalids? Maybe! They've certainly gotten the attention of dynamicist Esko Lyytinen. "This made me think that if the sky is clear here in Finland during the predicted shower, I will try to tune my fireball camera to observe in the daylight for a possible daylight fireball," he says.

Discovered in 2004, Comet 209P/LINEAR went through its perihelion on May 6th and will pass just 5 million miles (0.055 astronomical unit) by Earth on May 29th. That will be the 9th closest approach of any comet on record. But the comet itself won't get any brighter than 11th magnitude at best. Besides, the meteors we'll see are not from this pass — instead, they'll be from perihelion passes as long ago as the late 1700s and early 1800s.

Adding to the uncertainty is that while the comet is active now, it might not have been all those years ago. "We do not know what rate to expect, because the comet was not observed in the 18th, 19th and early 20th centuries," explains meteor specialist Peter Jenniskens (SETI Institute).

For those who might have the misfortune of cloudy weather during the Camelopardalid shower — or if you live where it won't be seen — Italian astronomer Gianluca Masi (Virtual Telescope Project) is planning an online meteor watch. "We will have several observers in the U.S. and Canada using wide-field imaging and all-sky cameras to send us images, assuring live coverage," he says. Coverage begins at 5:30 Universal Time May 24th.

You can also watch a webcast using the Slooh robotic telescopes. The Slooh team will view and discuss the comet starting at 6 p.m. EDT (22:00 UT) and follow with live coverage of the new meteor shower a few hours later at 11 p.m. EDT (3:00 UT May 24th).

Should this event tempt you to pull out your camera, read our article on How to Photograph a Meteor Shower for equipment and techniques that will help you toward success.