The December 25 partial solar eclipse

Observer's Notebook for December, 2000

by John Rummel

Late this month, on Christmas day, a partial solar eclipse will be visible from the United States (except Alaska and Hawaii), Canada, Mexico, Central America, the Caribbean and the North Atlantic. In Madison, approximately 56% of the sun's disk will be covered at greatest eclipse. Since the central part of the moon's shadow, the umbra, misses the earth entirely, there will be no "total" eclipse visible on this, the last eclipse of the millennium.

For observers in Madison, the partial eclipse begins at about 9:43 AM, reaches maximum at 11:18 AM, and ends at 12:48 PM. Even though a little more than half the sun's disk will be obscured, the actual drop in light levels will be virtually unnoticeable. Unless you're watching the sun, you won't notice anything at all. There will be no daytime roosting of birds, no unusual animal behavior, no drop in air temperature - all events regularly reported by observers of total solar eclipses. This plus the fact that it happens on the morning of Christmas may conspire to make it a relatively unobserved event. Many may find it difficult to break away from family get-togethers and holiday celebrations. If you get clouded out or just can't get an opportunity to view this eclipse, you'll have a few more chances in the next several years. Madisonians will see partial eclipses on December 14, 2001, June 10, 2002, May 20, 2012, and October 23, 2014, but these will all be very late afternoon events, where the sun will actually set while in a partially eclipsed state. This month's event is visible from beginning to end while the sun is high in the sky.

The big enchilada is coming up on August 21, 2017 - the next opportunity for the continental United States to view a total solar eclipse. The path of totality will follow a line from Oregon to South Carolina. Madison observers will see a deep partial eclipse but most diehard observers will want to drive to southern Illinois or Missouri to see totality. Mark your calendars.

 
Eclipse map courtesy of Fred Espenak, NASA/Goddard Space Flight Center. For more information on solar and lunar eclipses, see Fred Espenak's Eclipse Home Page.

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