When Galileo first looked through his telescope at Saturn, he thought it had two large companion planets on either side of it. He probably saw something like this:

Once he saw them seem to shrink and disappear, and then return. We know now that Saturn has rings, which looked like large companions in Galileo's small and primitive telescope — and when they seemed to disappear, he was actually seeing the rings edge-on.

This happens every fifteen years, when the Earth crosses Saturn's ring plane. The last such crossing, in February 1996, was relatively easy to observe, as Saturn was setting a few hours behind the Sun at the time. This year we aren't so lucky; on September 4, when we cross the ring plane, Saturn will be a mere 10° away from the Sun in our sky. It won?t be safe to observe with an Earth-bound telescope.

Fortunately, Starry Night is here to simulate the view: