Rare lunar eclipse Tuesday morning

Early on Tuesday morning (December 21, 2010), a total lunar eclipse will be visible across all of North America. A total lunar eclipse is when the full moon is gradually covered by the Earth’s shadow and plunged into total darkness, before the shadow moves past and the moon returns to it’s full brightness.1

This particular lunar eclipse is extremely rare because it is occurring on the day of the winter solstice (the longest night of the year). While regular lunar eclipses occur about every 4.5 years, a winter solstice eclipse such as this one only occur every 400–500 years.2

Tuesday’s event begins at about 12:33 AM CST (Milwaukee time) and will end just after 4:00 AM CST. As you watch, the Earth’s shadow will first begin to cover the moon’s upper left edge and gradually move across and cover the entire moon. The moon will be completely in the Earth’s shadow from 1:40 AM CST to 2:54 AM CST.3 So stay up late on Monday (or get up early on Tuesday) and don’t miss this once-in-ten-lifetimes event!

1. To learn more about lunar eclipses in general, and this lunar eclipse in particular, visit NASA’s Eclipse page. [↩]
2. After Tuesday, the next winter solstice lunar eclipse won’t occur until the year 2401, a very long wait if you miss Tuesday’s event. [↩]
3. You’ll notice that even when the moon is entirely covered by Earth’s shadow, it still has a faint glow. That glow is actually Earthlight — light reflecting off of the Earth — illuminating the moon. Cool, huh? [↩]