Weather permitting, North Americans will be able to see a total lunar eclipse tomorrow night. Depending on where you live, you’ll be able to see the eclipse sometime between 10:30 pm on December 20th (West coast denizens) to 5 am on the 21st (for those on the East coast).
Caption: Path of the Moon through Earth's umbral and penumbral shadows during the Total Lunar Eclipse of Dec. 21, 2010.
Credit: Fred Espenak/NASA's Goddard Space Flight Center
Lunar eclipses occur when the Earth moves directly between the sun and the moon. In this position, the Earth casts a shadow over the moon. If you get a chance to observe the lunar eclipse, you should see the moon change colors from gray through orange to deep red as the Earth’s shadow passes over it. And, by the way, you can safely observe these color changes with your own eyes, no special equipment required.
There won’t be another total lunar eclipse visible in North America for over three and a half years. So if there’s nice weather in your area, take the opportunity to see this one.