A total eclipse of the moon will be visible throughout all of North and Central America from 11:41 p.m. until 12:53 a.m. Tuesday, the first such eclipse in almost three years.

A total eclipse of the moon will be visible throughout all of North and Central America from 11:41 p.m. until 12:53 a.m. Tuesday, the first such eclipse in almost three years.

Weather permitting, observers will begin seeing the moon enter the Earth's inner shadow, or umbra, at 10:33 p.m. which appears as a red-brown shadow creeping across the bright moon. This shadow has a curved edge, taken as proof to at least some ancients that the Earth is round. The sky will get darker as the shadow progresses across the moon, and more stars will appear in the sky as sunlight reflected from the moon fades.

Totality will last a generous 72 minutes, then the process will reverse, with the moon completely emerging from the umbra at 3:01 a.m.

Unlike a total solar eclipse, when the sun is blotted out, a lunar eclipse rarely turns the moon totally black. Because of sunrises and sunsets around the world that scatter and refract light from the sun, the moon generally appears bright and coppery orange, or sometimes brown or dark red-black, depending on how much pollution is in the atmosphere.

The most recent total eclipse of the moon was on the night of Feb. 20-21, 2008.

Also unlike a solar eclipse, which can generally be seen only from selected places on the Earth's surface, a lunar eclipse can be seen from anywhere on the side of the Earth facing the moon.

The next lunar eclipse is on June 15, 2011, but North America will miss out because we will be facing the wrong way. Another eclipse will occur on Dec. 10, but it will be interrupted by moonset and sunrise.

The next total lunar eclipse for the entire continent doesn't occur until April 14-15, 2014, an unusually long wait.

NASA will be hosting Web chats about the eclipse and, for those encountering bad weather, showing it live at www.nasa.gov/watchtheskies.