Watch a 45-mile-wide asteroid blot out a star tonight

An asteroid the size of Rhode Island will briefly blot out one of the brightest stars in the sky overnight tonight (March 19-20), and you can watch the rare celestial event live online, weather permitting.

At around 2:05 a.m. EDT Thursday morning, a 45-mile-wide asteroid 163 Erigone will eclipse Regulus, as seen from a swath of North America, making the 22nd-brightest star in the sky disappear for a few seconds.

This "occultation" will be visible from the ground only to people in a narrow corridor in northeastern North America. However, the online Slooh Space Camera will offer live views of the eclipse during a show that begins at 1:45 a.m. EDT Thursday. You can follow it at www.slooh.com or watch the asteroid-Regulus webcast here, courtesy of Slooh. [Rare Asteroid Eclipse of Star Regulus: A Photo Guide]

"In my entire 40 years as a professional astronomer, I've never witnessed a star as bright as Regulus — Leo's 'alpha' luminary — being blocked as seen along a populated Earthly path in an easily accessible region," Slooh astronomer Bob Berman said in a statement.

"That's what will happen early Thursday morning," he added. "It’s hard to describe the excitement of this event. Regulus will vanish, and the constellation Leo will temporarily look totally different for as much as 14 seconds, as seen from New York City and about a 100-mile wide path extending to that city’s north and west."

The occultation holds more than mere gee-whiz appeal, researchers say. It also offers an opportunity to learn more about 163 Erigone, which circles the sun in the main asteroid belt between Mars and Jupiter.

"With accurate timing from a number of observers spread along the path, we can actually determine the asteroid’s size and shape to a remarkable degree of accuracy," Slooh host and observatory director Paul Cox said in a statement.

The eclipse of Regulus will be visible to skywatchers in New York City, as well as parts of New Jersey, Connecticut, upstate New York and Ontario.

Editor's note: If you snap a great photo of rare asteroid occultation of the star Regulus, or any other night sky view, and would like to share it with Space.com for a story or gallery please send comments and images to managing editor Tariq Malik at: spacephotos@space.com.

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Observers in New York City can design a (very late) night on the town around the occultation. The Intrepid Sea, Air and Space Museum and the Amateur Astronomers Association of New York are hosting a 163 Erigone-Regulus event tonight, from 11:59 p.m. to 2:30 a.m. EDT.

The free eclipse celebration will take place at the Intrepid Sea, Air and Space Museum, which is located at Pier 86 in Manhattan; visit the Intrepid website here for details and to RSVP (required).

"Intrepid Museum educators will be on hand to discuss and explain the occultation of Regulus prior to the cosmic event, which will take place a little after 2:05 AM EDT," museum officials wrote in a media advisory. "Guests are welcome to bring their own binoculars and telescopes; however, telescopes are not necessary to view the occultation."