Rare Triple Moon Dance on Jupiter
Attention all small telescope owners!
Next Tuesday, June 3rd, Callisto, Ganymede, and Io—three of Jupiter's largest moons — will all be casting their inky shadows upon our giant neighbor's surface at the same time.
This triple transit overlap is exciting because it's relatively rare. Unlike Io, the moon that is closest to Saturn and casts a shadow on its surface once every 42 hours, Callisto and Ganymede are slower to orbit the planet. Two of the four largest moons overlap simultaneously a few times a year. The overlap of three, however, happens less than once a year, the last time being last October 12, 2013, and the next January 24, 2015.
This unusual overlap will last almost two hours long, beginning at 2:08 pm EDT and ending at 3:56 pm EDT. But if you are in a rush and can only spend a minute or two on the gaseous giant, the best time to tune in will be around 2:15 EDT, because it's the moment at which the shadows are predicted to be most crisp.
Check out the computer simulation below for a preview of Tuesday afternoon's triple moon dance!
Credit: Starry Night Software
And for those of us who don't have easy access to a telescope, there's a simple solution. You can install a program like Starry Night and see the triple shadow cast with even more clarity and precision than you would on a microscope.
To plan your moon-viewing to the minute, check out Space.com's itinerary for Tuesday .