Haul out those binoculars and telescopes you bought to see Halley's Comet. Tonight, by the light of the gibbous Moon, Washington area residents will be able to see the lunar eclipse of Antares, one of the brightest stars in the universe.
Tonight's occultation -- or the lunar eclipse of a star -- begins in the southwestern sky when Antares vanishes behind the dark side of the Moon at 12:27 a.m. The star will reappear almost an hour later, emerging from the Moon's bright side at 1:24 a.m. Antares, the brightest star in the constellation Scorpio, is also known as Alpha Scorpii.
"You'll see the star shining in its full brilliance, then it'll look like it's stuck to the side of the Moon," said David Dunham of the International Occultation Timing Association. "Then, it disappears sharply."
This kind of quick blip proved to early astronomers that the Moon held no atmosphere, according to Dunham, who lives in Silver Spring. As Antares approaches the Moon, the star will not dim. If the Moon had an atmosphere, the star would blur.
Lunar eclipses of stars generally run in four-year series. The current occultations of Antares can be seen from all over the globe. But tonight will be the only view Washington gets this year, Dunham said. The Washington area's last visible occultation was in 1981 of Aldebaran, a bright red star in the constellation Taurus.
Dunham said that because of the geometry involved, most of the rest of Antares' lunar eclipses will be visible only from the Southern Hemisphere.
Antares' last series of occultations ended in 1969. Its current series of occultations began in March and will last until about 1990, Dunham said.