On the night of March 19th/20th, Asteroid (163) Erigone, a space rock 45­miles wide, will briefly eclipse the bright star Regulus, blacking it out entirely in the night sky. This phenomenon, known as an occultation, will occur around 2 AM EDT and last for up to 14­seconds dependent on the exact viewing location.

Slooh will cover the event live on Wednesday, March 19th at 10:45 PM PDT / 1:45 AM EDT (3/20) / 05:45 UTC (3/20) (International Times) with live feeds from New York. Viewers can watch free on or by downloading the Slooh iPad app. The live image streams will be accompanied by discussions led by Slooh host and Observatory Director Paul Cox, with Slooh’s astronomer Bob Berman reporting live from New York. In addition, Ted Blank from the International Occultation Timing Association (IOTA) will appear as a guest directly from his remote viewing location while also providing a live feed for broadcast. Viewers may ask questions during the show by using hashtag #Regulus.

The asteroid, (163) Erigone, orbits the Sun between Mars and Jupiter in the main asteroid belt. The star it will eclipse, Regulus, is the 22nd brightest in the sky with a magnitude of +1.3. Erigone’s shadow will race at nearly two miles per second along the ground, resulting in Regulus vanishing for between a fraction of a second to 14­seconds, depending on whether the observer is centrally located beneath the shadow, or near its edge. Observing the timing of this event at various locations will enable astronomers to determine Erigone’s size and shape to an unprecedented level of accuracy.
Says Berman,

“In the natural world, we generally think of the Sun as sometimes being blocked or eclipsed. But even stars can be momentarily eclipsed or blocked by a zooming planet or asteroid, and then that starlight briefly vanishes. This is called an occultation. But it’s rare for a truly bright star to be eclipsed. And even when this happens, the shadow of the asteroid is usually cast over some remote piece of ocean or wilderness. 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.

“That’s what will happen early Thursday morning. 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 100­mile wide path extending to that city’s north and west. Of course Slooh is stationing equipment that can bring this rare event live to the public who hopefully will set their alarms for a bit after 2 AM, to join us.”

Says Cox,
“Although the actual occultation of Regulus won’t be visible from Slooh’s primary observatory in the Canary Islands, Slooh members have already started nightly imaging of asteroid (163) Erigone as it makes its approach. But it’s the actual occultation that we’re really looking forward to – with me in the studio and Bob Berman giving us not only live images of the occultation, but also an eyewitness report.”

“There is more to an occultation like this than first meets the eye – it’s more than just a small white dot being snuffed out for 14­seconds; 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.”