Alert: Total Lunar Eclipse Set Thursday - Sun May 11, 4:16 PM ET

LOS ANGELES - If the weather cooperates, a total lunar eclipse will be seen across North America late Thursday — the first visible in the United States in three years — and just before dawn Friday in western Europe and western and southern Africa.

A lunar eclipse occurs when the Earth casts its shadow on the full moon, blocking the sunlight that otherwise reflects off the moon's surface. Unlike solar eclipses, lunar eclipses are safe to view with the naked eye.

In North America, the moon will remain totally eclipsed for 53 minutes, and should turn substantially darker and reddish in color.

The total eclipse will start at 8:13 PDT in Los Angeles, 11:13 p.m. EDT in New York.

--Watch the sky. It's watching you...