Jupitor with its four largest moon.

Jupiter and its four largest moon, as I have seen through a telescope last night 17th, sep 2011 (12:40 am)These four largest and brightest moons of Jupiter, first discovered by Galileo Galilei in 1610, are known as the Galilean satellites. the moons are Io, Europa, Ganymede, and Callisto. This order is also the order of increasing distance from Jupiter. Every six years the Earth lies in the orbit...al plane of Jupiter's moons. At this time Jupiter's 4 bright moons are directly in our line of sight, and the shifting of these moons, one in front of another, plus their shadows crossing the surface of Jupiter grab the attention of those with telescopes. The last time this occurred was in 2003. Once again in 2009 Earth is moving through the plane of Jupiter's satellites, allowing the moons to line up in their special 6-year geometry. -Christusohn Streber, IISER M INDIA