What Is a Total Lunar Eclipse? A total lunar eclipse occurs when the Moon passes into the shadow cast by the Earth. The round disk of the full Moon slowly moves into the dark shadow, and the bright Moon grows dim. The Moon, however, does not become completely dark. Instead, it glows with a faint copper or red color, a result of sunlight being filtered and bent through the Earth's atmosphere (like a sunset). How to Watch the Eclipse. If skies are clear, the lunar eclipse will be visible throughout southern California and can be seen with the unaided eye. All you need to do is look up! See the timeline below. Telescopes or binoculars will enhance the view.