by Robert Vanderbei
On Monday, Dec. 21, Jupiter will “lap” Saturn in their mutual race around the Sun. At the closest approach, their angular separation will be just 6 arcminutes. That’s the closest Jupiter/Saturn conjunction in about 400 years. And, it will happen on the day of the winter solstice. This will be an interesting event to see especially if viewed through a telescope. In preparation for the event, I have in recent weeks taken some pics of Jupiter and Saturn using my 10-inch Ritchey-Chretien telescope. Shown here is a mosaic image I made from two distinct pictures, one of Jupiter and one of Saturn taken at about 4:45pm on December 10. I made the mosaic showing what a 6-arcminute separation would look like. By the way, one of the really cool things was that my picture of Jupiter also has Ganymede, Europa and Callisto in it. That’s pretty cool given that it was only just a few minutes after sunset when I took that picture. It was not yet dark outside.