Volume: 01, Issue: 16 11/05/2003 
An image of a lunar eclipse taken by astrophotograph Doug Murray. He left his shutter open during the entire eclipse to demonstrate the change in the moon's appearance.
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Other Articles in This Issue:
Double Your Viewing Pleasure
California Wildfires Captured by International Space Station Crew
Astronomers Find Nearest Galaxy to the Milky Way
A Week of Extraordinary Solar Activity
 

Total Lunar Eclipse the Night of November 9

For the second time this year we will be privy to that peculiarity of the celestial clockwork known as the lunar eclipse. On Saturday, November 8, 2003, for six hours, the Earth's shadow will crawl across the Moon, completely engulfing it and then receding away.

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.

Most of us should be able to observe at least part of this event, but for most of America the moon will rise while already in eclipse. At 4:15 PM CST on November 8th, 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 those of us not living in the northeast, this will occur while the Moon is beneath the eastern horizon. A little over an hour later, at 5:32 PM CST, the Moon will pass into the umbra, and the total eclipse will begin. For the 24 minutes between 7:06 PM CST and 7:30 PM CST, the Moon will completely dip into the shadow of the Earth and resurface on the other side. By 10:21 PM CST, 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 perhaps a warm coat.

To learn more about lunar eclipses, check out:
http://sunearth.gsfc.nasa.gov/eclipse/lunar.html

    
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