Everything you need to know to catch Sunday's rare "ring of fire"…

This weekend, the Moon will pass between Earth and the Sun, giving rise to what sky-watchers call an annular eclipse. Also known as a "ring of fire" eclipse (for reasons that the top image should make clear), it's the first annular eclipse to be visible from the continental U.S. in close to 20 years. Here's what you… » 5/18/12 1:25pm 5/18/12 1:25pm