By Dr. Tony Phillips
Dec. 23, 2011:T'was the Night after Christmas and all through the house, not a creature was stirring ...
...because everyone was outside watching the planets align?
It's true. On Dec. 26th, the night after Christmas, Venus and the slender crescent Moon will gather for a jaw-dropping conjunction in the western sky.
The action begins shortly before sunset. Around 4:30 pm to 5:00 pm local time, just as the sky is assuming its evening hue, Venus will pop into view, glistening bright in the deepening twilight. No more than 6 degrees to the right lies the crescent Moon, exquisitely slender, grinning like the Cheshire cat with his head cocked at humorous attention. This is a wonderful time to look; there are very few sights in the heavens as splendid as Venus and the Moon gathered close and surrounded by twilight blue.
But don't go inside yet, because the view is about to improve. As the sky fades to black, a ghostly image of the full Moon materializes within the horns of the lunar crescent. This is caused by Earthshine, a delicate veil of sunlight reflected from our own blue planet onto the dusty-dark lunar terrain. Also known as "the Da Vinci glow," after Leonardo da Vinci who first understood it 500 years ago, Earthshine pushes the beauty of the conjunction over the top.
Meanwhile, Jupiter will be looking down on it all from a perch overhead in the constellation Pisces. In ascending order, Jupiter, Venus and the Moon are the three brightest objects in the night sky, able to pierce city lights and even thin clouds. Almost everyone, everywhere will be able to see them.
Although no telescope is required to enjoy the show, if one happens to be under your Christmas tree, take it outside. With a simple triangular sweep, you can see the clouds and moons of Jupiter, mountains and craters on the Moon, and the fat gibbous form of Venus. (Like the Moon, Venus has phases, and at the moment she is 83% illuminated.) Rarely can so much amateur astronomy be done with so little effort.
Some people find the night after Christmas to be a bit of a letdown. This year, it's not so bad.
Last Updated: 23 December 2011