Tonight – as soon as the sky begins to darken after sunset – look west for a very slim crescent moon and the brightest planet Venus. Although the moon and the planet Venus rank as the brightest and second-brightest orbs of nighttime, respectively, it’ll take a big effort to spot these two brilliant beauties after sunset on December 22, 2014. You’ll need an unobstructed horizon in the sunset direction. Start your search no more than half an hour to 45 minutes after sunset. If you have crystal-clear skies, you may have a window of opportunity lasting 15 minutes or so before the young moon and Venus follow the sun beneath the horizon. Binoculars will be helpful!
For North America, and possibly in Europe and/or northwestern Asia, this evening tantalizes you with a chance to catch a young lunar crescent that’s less than 24 hours old. The moon turned new on December 22 at 1:36 Universal Time. Translating Universal Time to the clock times at U.S. time zones, the new moon happened on December 21 at 8:36 p.m. EST, 7:36 p.m. CST, 6:35 p.m. MST and 5:36 p.m. PST.
You may well need an optical aid to spot the pale, super-thin lunar crescent in the fading embers of evening twilight. The Northern Hemisphere has the big advantage in the hunt for the young moon this evening, because the moon lies maximally north of the ecliptic – Earth’s orbital plane. A young moon to the north of the ecliptic sets all the later after the sun at northerly latitudes but all the sooner after sunset at southerly latitudes.
There’s another factor that makes the young moon easier to spot than the average young moon. The moon is only a few days shy of reaching lunar perigee – the moon’s closest point to Earth in its orbit – so the young moon is traveling eastward, or away from the sun at a faster clip than it normally does. So, who knows? This evening may be your chance to spot a ghostly-looking lunar crescent that’s less than 24 hours old.
If you miss seeing the young moon and Venus after sunset on December 22, keep watching the evening skies. The moon will be appearing a little higher in the sky each evening after sunset. It’ll pass the red planet Mars in the coming few days – a wonderful consolation prize!
By the way, Venus will become much easier to see in the coming weeks. The planet Mercury will also be appearing in the sunset sky. Watch for all these planets in the weeks ahead! Click here for EarthSky’s guide to the visible planets.
Bottom line: Look for the moon and Venus very, very low in the sky – sunset direction – after the sun goes down on December 22, 2014. Miss ‘em? Try for the moon and Mars in the next few evenings.