Regulus, one of the brightest stars in the sky, is set to disappear for up to 14 seconds tonight, giving amateur astronomers a once-in-a-lifetime chance to see such an event. The star will be eclipsed by the asteroid 163 Erigone, and would normally be visible over parts of the northeastern United Sates and southeast Canada. However, clouds may keep people from seeing the ultra-rare occultation.
Just past 2 a.m. EDT on Thursday morning, the large asteroid 163 Erigone will pass directly between the Earth and the star Regulus, in the Constellation Leo.
The occultation will be visible, weather permitting, in a swatch of land stretching across several states. On the west, the event will be visible in locations ranging from just east of Rochester in New York, to just slightly west of the Big Apple. The easternmost area where this occultation may be seen extends from Ottawa in Canada, roughly down through Albany, and New Haven, Connecticut.
Weather reports for Rochester and New York City predict cloudy skies, with a 100 percent chance of precipitation. Ottawa has a 90 percent chance of snow, and heavy rains are in the forecast for New Haven.
The asteroid that could create that exciting view is 45 miles across, and orbits around the Sun, as a member of the asteroid belt between Mars and Jupiter. Carbon makes up a large portion of the makeup of 163 Erigone, giving it a dark color.
Similar asteroid occultations of stars occur every day, but nearly all of them take place in front of stars too dim to see with the naked eye. Tonight's event is one that may not happen again for decades.
If clouds break in your area, go outside around 2 a.m. EDT. Look to the west-southwest, about halfway up above the horizon. There, you will find the constellation Leo, looking like a lion, facing to the right, and slightly downward. Regulus will be the bright star in the bottom front of the figure. Some people think the front of the figure looks like a backward question mark, with the dot being Regulus.
No special equipment is needed to see this event, if clouds do not block the view. Remember to dress so that you stay warm and dry. The main event should take place at around 2:06 in the morning, and could last anywhere from a fraction of a second to 14 seconds, depending on your location, and the exact shape of the asteroid.
Anyone who is able to see the star is encouraged to time how long the star is blacked out, then send that information to the International Occultation Timing Association.
