Jupiter at Opposition Tonight

Jupiter makes its closest approach to Earth tonight...it's closest approach until 2022. We call this opposition since Jupiter and the Sun are 180 degrees from each other in the sky (or on opposite sides of the sky). Jupiter moves around the Sun more slowly than Earth so Earth catches up to Jupiter and passes it about every 13 months.

However, Jupiter and Earth do not have perfectly circular orbits. Therefore sometimes they get a little closer together than other. Jupiter is closer to the Sun than average so this a a closer pass than normal. Jupiter appears a little brighter than usual (and, through a telescope, larger than usual. You won't see much besides a bright dot naked eye).

Friday night I am pretty sure I had the rare experience of seeing Jupiter's Moon Callisto naked eye. We checked and what I was seeing matched where Callisto was. Callisto was very far away from Jupiter that night as well. At its farthest, you can just barely pick it out. Jupiter being closer than average may have helped as well.

Jupiter rises in the east at Sunset. It will be highest in the sky at midnight, and set at dawn tonight. Jupiter will rise a few minutes earlier each night. If you can't see it tonight, don't despair. The distance between Earth and Jupiter changes slowly so it will be almost as good for a few weeks and slowly dim (even at its "dimmest" Jupiter is still brighter than any star in the sky!)

A steady hand with binoculars can reveal Jupiter's Moons. A small telescope starts revealing Jupiter's bands. The next couple of months are Jupiter season so go take a look.

Reprinted with permission from the Half-Astrophysicist Blog.