Oppositions of Jupiter happen every 13 months, but this one is special. In a rare coincidence, Jupiter's opposition on Feb. 6th coincides almost perfectly with its equinox on Feb. 5th when the Sun crosses Jupiter's equatorial plane. It is an edge-on apparition of the giant planet that sets the stage for a remarkable series of events. For the next couple of months, backyard sky watchers can see the moons of Jupiter executing a complex series of mutual eclipses and transits.
For instance, on Feb. 5th, volcanic Io will cast its shadow on Ganymede, Jupiter's largest moon.. Two days later, on Feb. 7th, icy Europa will cast its shadow on Io. Events like these will continue, off and on, until July 2015. Look up at midnight for the brightest light from the outer solar system you'll see all year.