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Total Lunar Eclipse on 2/20/08!
By Linda | February 20, 2008
On Wednesday evening, February 20th, the full Moon over the Americas will turn a delightful shade of red and possibly turquoise, too. It’s a total lunar eclipse—the last one until December 2010!
This graphic by Larry Koehn depicts the sequence of the lunar eclipse in the Central Time Zone
The Sun goes down. The Moon comes up. You go out and look at the sky. Observing the eclipse is that easy. Maximum eclipse, and maximum beauty, occurs at 10:26 pm EST (7:26 pm PST).
A lunar eclipse happens when the Moon passes through the shadow of Earth. You might expect the Moon to grow even more ashen than usual, but in fact it transforms into an orb of vivid red.
Why red? That is the color of Earth’s shadow.
Consider the following: Most shadows we’re familiar with are black or gray; step outside on a sunny day and look at your own. Earth’s shadow is different because, unlike you, Earth has an atmosphere. The delicate layer of dusty air surrounding our planet reddens and redirects the light of the sun, filling the dark behind Earth with a sunset-red glow. The exact tint–anything from bright orange to blood red is possible–depends on the unpredictable state of the atmosphere at the time of the eclipse.
Transiting the shadow’s core takes about an hour. The first hints of red appear around 10 pm EST (7 pm PST), heralding a profusion of coppery hues that roll across the Moon’s surface enveloping every crater, mountain and moon rock, only to fade away again after 11 pm EST (8 pm PST). No special filter or telescope is required to see this spectacular event. It is a bright and leisurely display visible from cities and countryside alike.
While you’re watching, be alert for another color: turquoise. Observers of several recent lunar eclipses have reported a flash of turquoise bracketing the red of totality.
The source of the turquoise is ozone. Eclipse researcher Dr. Richard Keen of the University of Colorado explains: “During a lunar eclipse, most of the light illuminating the moon passes through the stratosphere where it is reddened by scattering. However, light passing through the upper stratosphere penetrates the ozone layer, which absorbs red light and actually makes the passing light ray bluer.” This can be seen, he says, as a soft blue fringe around the red core of Earth’s shadow.
To catch the turquoise on Feb. 20th, he advises, “look during the first and last minutes of totality.” That would be around 10:01 pm EST and 10:51 pm EST (7:01 and 7:51 pm PST).
Via NASA
Topics: In the News, Nature, The Cosmos |
