Eclipses occur when the moon moves into a position where it is directly aligned with the sun and the earth. At this time the sun, the earth and the moon must be very nearly, if not precisely aligned.

There are two basic types of eclipses – lunar and solar. A total LUNAR ECLIPSE occurs when the full moon passes through the shadow of the earth. In this case, the earth is between the sun and the moon. During a lunar eclipse you can see the bright moon darken - sometimes to a reddish brown color. A lunar eclipse can last for an hour or more.

A total SOLAR ECLIPSE occurs when the new moon passes directly between the sun and the earth. For a few minutes, the moon totally obscures the bright sun and casts a narrow shadow on the earth, turning daytime into an eerie darkness. This narrow shadow on the earth is called the umbra. The umbra sweeps across the earth at over 1,000 miles an hour. The umbra in 2002 will be no wider than 120 miles across.

Just outside this narrow path of totality, there is a partial shadow called the penumbra, where a section of the sun’s bright disk can be seen.

Before totality, a phenomenon called "Bailey’s beads" occurs. The beads appear around the edge of the moon, when the last rays of sunlight shine though the irregularities of the moon's surface.

During totality birds begin to roost; nocturnal animals prepare to start their day; diurnal animals prepare for the night; and the stars become visible. It is during these few minutes as the moon totally obscures the sun, that the sun’s halo, the corona, comes into view.

Total solar eclipses are rare. They do not occur every month. This is because the orbit of the moon is tilted by about five degrees in relation to the earth’s orbit. And normally the moon passes just above or below the line between the sun and the earth. So at most new and full moons, the shadows miss the earth and there is no eclipse. The right eclipse conditions occur about every six months.

There are fewer than 70 total solar eclipses each century, so for most folks, this is a once-in-a-lifetime happening!

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