About a half hour to an hour after local sunset, the waxing crescent moon will dominate the southwest sky. A bright white “evening star, which is actually the planet Venus, will shine about seven degrees below the moon, making for a stunning pairing easily visible with the unaided eye.
At dusk the moon will position itself to the right of ruddy Mars. The two objects will be less than three degrees apart, equal to about six lunar disks. The red planet currently sits 117 million miles from Earth, which means that light and radio signals take nearly 11 minutes to travel one way between our worlds.
At 1:25 p.m. ET (18:27 UTC) on the 12th, the nearly full moon — or what astronomers call the waxing gibbous moon — will reach its closest point to Earth in its monthly cycle, at a distance of only 222,738 miles. The coincidence of a full moon and the lunar orb’s closest approach is popularly dubbed a supermoon, and December’s event will be the third in as many months. (Also see 11 striking pictures of the November supermoon, the closest to Earth since 1948.)
The moon will officially reach its full phase just a little over day later, at 2:06 p.m. ET (19:06 UTC) on December 13. Either night, it will be worth taking a look at the silvery orb rising in the east around the time of local sunset.
Meanwhile, try using binoculars or telescopes to spot the bright orange star Aldebaran near the moon. For lucky sky-watchers across most of North America and Western Europe, the red giant star, part of the constellation Taurus, the bull, will get briefly eclipsed by the moon at 11:13 p.m. ET (4:05 UTC).