Total Lunar Eclipse

Feb. 13, 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 Dec. 2010.

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. “Only the shadow knows,” says astronomer Jack Horkheimer of the Miami Space Transit Planetarium.

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 blue and turquoise shades at the edge of Earth’s shadow were incredible,” recalls amateur astronomer Eva Seidenfaden of Trier, Germany, who took the picture at right during the European lunar eclipse of March 3-4, 2007. Dozens of other photographers have documented the same phenomenon.

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).

Blood red, bright orange, gentle turquoise: it’s all good. Mark your calendar in vivid color for the Feb. 20th lunar eclipse.

Source: NASA.

I can hardly wait! Hopefully it will be a clear night.

9 Responses so far »

  1. 1

    Robert D said,

    I marked it on the calendar last week, in Red no less.

  2. 2

    swampie said,

    I’m likely to completely forget about it unless I’m reminded that very day.

  3. 3

    swampie said,

    I did not know the earth’s shadow was red. NASA better not be pullin’ my leg.

  4. 4

    Robert D said,

    The bad news for me…rain and snow begins again Monday, dangit!

  5. 5

    swampie said,

    Dang, Robert D, what are y’all doing, trying to accelerate global warming by drawing all the coldness to California where it can eventually be melted?

  6. 6

    Robert D said,

    We are taking our share, but it looks like we’re sharing plenty with Colorado

  7. 7

    swampie said,

    We’ve had another 2 days of freezing temperatures just when the azaleas and fruit trees started blooming and the grass was breaking dormancy (again). I’m putting out lotsa bucks for hay that I can’t afford.

  8. 8

    swampie said,

    Snow flurries in Hotlanta yesterday, too. We should rebound up to near 80 over the weekend and what comes after that, who knows.

  9. 9

    Robert D said,

    We’re supposed to get to the 60’s this weekend, but the overnight temps will still be 20-25 degrees. We have a lot of stop and go springs around here. It plays hell with the plant life.

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