What Are Eclipses?

The Earth may be the only place in the Solar System where we can view a Total Eclipse of the Sun. I find that rather remarkable. The geometry of the Earth-Moon-Sun relationship is just right for viewing these phenomena. The diameter of the Sun is approximately 400 times larger than the Moon, but it is also approximately 400 times further away from us than the moon. That means that the Sun and the Moon appear to be the nearly the same size (about 1/2 degree) as we see them from the Earth. On those rare occasions when the Moon actually passes between the Earth and the Sun, it blocks the Suns "surface", which is dazzlingly bright, and allows us to see the faint, yet still bright atmosphere called the corona.There may also be flares and prominences visible.

The most difficult part about observing a total solar eclipse is that the Moon's shadow is no more than 150 miles across at the surface of the Earth. So any given total solar eclipse can be seen from only a small area of the Earth's surface.To see one, you will probably have to travel, maybe a great distance. The path of the eclipse of March 29, 2006 is in Africa and Asia. While it is mostly over land, I have found that it is hard to be a ship as great way to travel.

Viewing a Total Eclipse

Contrary to what you may have heard, Total Solar Eclipses are safe to view without any optical aid or protection! What is potentially dangerous is looking at the Sun at ANY TIME OTHER THAN a Total Solar Eclipse. That includes the partial phase of an eclipse. DO NOT LOOK DIRECTLY AT THE SUN AT ANY TIME, unless you happen to be watching a total solar eclipse. Then it's OK.

Some Helpful Information and Resource Links

• NASA's Astronomy Picture of the Day is a great place to get great photos and useful information. Here's one of a total solar eclipse, one of a partial solar eclipse and one of an annular eclipse.
• Another NASA eclipse page maintained by Fred Espanek at Goddard Space Flight Center.
• This is a Quicktime movie by Fred Espanek of the November 3, 1994 eclipse in South America. (Careful, this is a huge file!)
• Earth View, Inc. has a fine page describing eclipses with diagrams.
• Another nice page on the 2006 eclipse.

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