Look to the skies Saturday morning for 'blood moon', total lunar eclipse

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(CNN) -- Sky watchers in western North America are in for a treat: a nearly five-minute total lunar eclipse just before sunrise on Saturday.

A lunar eclipse happens when the sun, earth and moon form a straight line in space, with the Earth smack in the middle. The sun shines on the earth and creates a shadow. As the moon moves deeper into that shadow, it appears to turn dark and may even appear to be a reddish color.

Starting at 3:16 a.m. Pacific daylight time Saturday, the moon will begin moving into Earth's shadow. For the next hour and 45 minutes, that shadow will move across the moon and engulf it at 4:58 a.m.

The total eclipse will only last four minutes and 43 seconds, and NASA says that makes it the shortest one of the century.

While people west of the Mississippi river will have the best view, at least a partial eclipse will be visible across the nation.

But sunrise will interrupt the show on the east coast.