Thursday, December 16, 2010

Early Celestial Christmas Gift

The early holiday present comes in the form of a total lunar eclipse, one of the sky's most intriguing sights.

(Lunar eclipse of August 28, 2007, composite image by Dan Glomski)

A lunar eclipse results from the Moon passing through Earth's shadow. During totality, the Moon can appear bright orange, reddish, coppery, brown, or black, depending on the shadow's color.

While this show costs nothing monetarily, you'll pay a little in terms of sleep; the eclipse doesn't begin until after midnight on the 21st. If this is an issue, consider observing the first part of the show only. Start from the time the Moon starts entering the dark inner portion of the shadow -- around 12:32 a.m. -- to about 2 a.m., about 20 minutes after the eclipse has become total.

(Eclipse timings on right listed in Universal Time;
subtract six hours from UT to convert to Central Time.
Click on image for larger version.
Eclipse predictions by Fred Espenak, NASA/GSFC

If sky conditions are favorable, the Sachtleben Observatory of Hastings College will be open for viewing. Call 402-462-7378 after 5 p.m. for a possible cancellation if clouds interfere. I'll have the coffee pot on for you, and perhaps some sugary treats to keep you awake and energized. And if it's cold on the observing deck, the warm classroom is always there.

Some ancient peoples could predict when eclipses might occur. A modern recreation of an eclipse-predicting device dating to the 2nd-century B.C.E. can be seen here:

Our next chance at a total lunar eclipse is April 2014. So if the skies are good enough to see the Moon next Monday night . . .

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