Don’t nod off too early after your Christmas feast or you’ll miss the astronomical dessert. Jupiter and the moon will be stacked like strawberries on shortcake all night long.
You may remember their conjunction last month, but this time around the duo will make an even more compact pair. They’ll be just a half degree or one moon diameter apart when closest around 5:30 p.m. (CST). Throw on a coat, walk outside and face east during evening twilight or later to get a good look.
The two will rise together side by side in the northeast around 2:30 p.m. that afternoon only 1 degree – two full moons – apart. Just before sunset, the moon will be high enough in the sky to sight Jupiter through binoculars to its upper left. Three hours later, the moon lines up under Jupiter in conjunction and then slowly slides away from the planet overnight.
When darkness falls and the presents have been opened, you’re in for a great sight and a wonderful way to top off the holiday. Could it have been a similar conjunction of the moon and brilliant Jupiter in the eastern sky that inspired the Magi of the Bible on their storied journey? Other planetary conjunctions, a nova and even a supernova have been proposed, but we’ll probably never know the exact explanation for the “star in Bethlehem”.
Binoculars users who can steady their instruments on a tripod or other reinforcement can see three of Jupiter’s four brightest moons Christmas evening. The 4th moon Io is too near the planet to see without a telescope.
Telescope users who are out early – before 6:15 p.m. CST – should watch for the tiny, pitch black shadow of Io along the edge of Jupiter’s Southern Equatorial cloud belt. The event is called a shadow transit and ends at 6:17 p.m.
Later around 10:30 p.m., the Great Red Spot rotates around from the east and remains visible until about 1 a.m. Look for a pale red-orange oval indentation in the SEB. Expectation warning – the feature is rather delicate, not nearly as dark and obvious as you’ve seen in photos. But if the air is steady and your telescope’s optics have had time to cool down, a 6-inch or larger scope will show it well.
Merry Christmas from the sky!