What’s happening in December’s skies? Close approach of the crescent moon, Mars and Neptune and a New Year’s Eve comet!
On Sunday night the crescent moon appears close to the red planet Mars. The two are in the zodiacal constellation Aquarius. This is not the same Mars you saw several months ago. Same planet, but Mars has lost much of its brilliance. There is not a visible planet in our night sky that can go through such a range of brightness. Mars is now a distant planet, nearly three times farther away from us than it was early last spring. Mars is now 133 million miles away. In May, Mars was glowing, in opposition, and it was a close 46 million miles away.
Venus: We gain about two additional minutes of Venus viewing each night this month, setting close to 7:05 p.m. on the 1st and 8:20 p.m. on the 31st. After the Moon, Venus is the brightest object in the sky after sunset and should jump right out at you to the southwest. You’ll have plenty of time to work on training your eyes to see first sight of Venus in the sky, as it remains with us near sunset until well into March 2017. Mars will hand off its close approach duties to Venus in January, when Venus and Neptune appear very close in the sky on Jan. 12.
Mercury: Mercury will be a tough catch this month, as it is not particularly bright and is very close to the horizon at sunset. Your best chance to see it will be on Dec. 15, when it will be nearly perfectly southwest after sunset and all but gone before 6 p.m. That said, Mercury will be in roughly the same position and early-setting until around the 20th. If you can find Mercury, Venus and Mars will be much easier catches as you swing your sights higher and to the south.