Volume: 01, Issue: 03
This photograph by Joe Orman is a four hour exposure of a lunar eclipse that took place on January 20, 2000.
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Other Articles in This Issue:
Soyuz Spacecraft Lands Short of Destination
Mercury to Pass In Front of Sun on May 7
Professional Development Opportunity in Astrobiology and More
 

Total Lunar Eclipse the Night of May 15

During their relentless waltz around the Sun, the Earth and Moon will have occasion to cast their shadows upon one another. Such will be the case on the night of May 15 when, for three hours and 15 minutes, the Moon will slip through the shadow of the Earth. If you live in the Americas, Europe, or Africa, and the weather is cooperative, you should be able to witness this event.

A lunar eclipse only occurs when the full moon passes through the shadow of the Earth. This shadow is essentially a small cone of darkness inside a larger but less dark cone. The large cone is known as the penumbra. In the penumbra, Earth blocks only a portion of the Sun's light. In the umbra—the smaller, darker cone—all direct sunlight is blocked by the Earth. While the Moon is in the umbra, a total lunar eclipse occurs.

At 9:03 PM CDT on May 15, 2003, the Moon will move into Earth's penumbra. This will only be noticeable to observers on Earth as a blurring of the Moon's details. For many of you living west of the Mississippi, this will occur while the Moon is beneath the eastern horizon. A little over an hour later, at 10:14 PM CDT, the Moon will pass into the umbra, and the total eclipse will begin. For the next 53 minutes, the Moon will completely dip into the shadow of the Earth and resurface on the other side. By 12:18 CDT the next morning, the Moon will have left the penumbra, and the entire eclipse will be over.

While the Moon is deep in Earth's umbra, it will not actually disappear. During this time, some of the Sun's light will still reach the Moon, but not directly. If you were to stand on the Moon and watch the Earth eclipse the Sun during this time, you would see a ring of light surrounding the Earth much in the same way we can see a ring of light surrounding the Moon during a solar eclipse. This light will reach the Moon, but first it must pass through Earth's atmosphere. Our atmosphere will filter out the shorter, bluer wavelengths of light, so that the light reaching the Moon will be in the orange and red end of the spectrum. This is the same principle behind the vivid colors of sunsets.

Perhaps the best part of lunar eclipse is the fact that there is no special equipment required for observation. All you need is a clear night and the will to stay up past your bedtime.

There have been partial lunar eclipses visible from the Americas as recent as November of last year, but the last total lunar eclipse occurred over two years ago. The next one, however, will be no further than November of this year.

For more information on lunar eclipses, visit:
http://sunearth.gsfc.nasa.gov/eclipse/extra/TLE2003May15.html

And:
http://www.mreclipse.com/Special/LEprimer.html

    
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