Sky watch: Total lunar eclipse on Dec. 20, 21

One of nature's greatest cover-ups will occur in two weeks, and you definitely won't want to miss it!

At dusk on Monday, Dec. 20, the full moon will rise normally over the northeastern horizon, but later that evening, it will undergo a total lunar eclipse.

The eclipse will begin at 12:29 a.m. on Tuesday, Dec. 21, when the full moon slips into Earth's light outer shadow (the penumbra). Not for another half-hour or so, however, will most of us detect much difference in the moon's appearance.

Then, at 1:32 a.m., the moon's eastern edge will enter the Earth's dark inner shadow (the umbra).

For the next hour or so, the moon will dim in the advancing shadow until around 2:40 a.m., when the moon becomes completely engulfed.

During totality, the moon may take on a strange coppery hue and, for viewers under a clear, dark rural sky, will appear to hang eerily among some of the most brilliant and colorful stars in all the heavens, those of the famous Winter Hexagon. This color occurs because sunlight passing through our atmosphere is reddened and bent inward toward the darkened surface of the eclipsed moon.

Totality lasts until 3:53 a.m., when the moon's eastern edge emerges into bright sunlight. Now, the umbral shadow continues to retreat westward across the lunar face, leaving it fully at 5:01 a.m.

Unlike a solar eclipse, it's safe to view a lunar one without a protective filter. If you've got binoculars or a small telescope, you may find viewing through using them even more enjoyable.

To find who might host a free lunar-eclipse viewing party in your area, check with your local planetarium, observatory, college or amateur astronomy club. And to learn more about lunar eclipses, visit

mreclipse.com/Special/LEprimer.html.

Let's hope clouds don't block our view of this cover-up because the next total lunar eclipse visible throughout the U.S. won't come until April 2014.