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Eclipses Through the Ages

April 2, 2015

In May of 1492, as Christopher Columbus was preparing to cross the Atlantic in search of a shorter route to Asia, a barely-there lunar eclipse took place over Europe. The Moon just grazed Earth’s faint outer shadow, beginning a new eclipse series that would last for centuries.

The 30th eclipse in that series — a total eclipse — takes place early Saturday, with all or part of it visible across the United States. The Moon will set before or during totality across the eastern half of the country. The western half will see all of the total eclipse, and at least some of the partial eclipse, as the Moon exits the shadow.

Diagram of an eclipse Saros cycleDiagram of an eclipse Saros cycleAn eclipse series is known as a Saros. The circumstances for each eclipse in the group are similar. The Moon is about the same distance from Earth, for example, and the eclipses occur at the same time of year.

Each Saros begins with a bare penumbral eclipse, like the one in 1492. With each succeeding eclipse, though, the Moon dips a little deeper into the shadow. By the middle of the cycle, the eclipses are total, with the Moon totally immersed in the shadow. After that, the Moon moves away from the center of the shadow, and the cycle ends with the Moon at the opposite side of the shadow from where the cycle began.

This eclipse is part of Saros 132. It will consist of 71 eclipses in all, with each one coming a bit more than 18 years after the previous one. Its final eclipse will take place in the year 2754.


Script by Damond Benningfield, Copyright 2015

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