Celestial Events 



Ring of Fire 



by Gail S. Cleere 



A total solar eclipse is perhaps the most 

 spectacular celestial event, but unfortu- 

 nately, at any given location, it is very rare: 

 the next one visible in the continental 

 United States will occur on August 21, 

 2017. (In all of recorded history, the sun 

 has never been totally echpsed over Wash- 

 ington, D.C., where I write.) On May 10, 

 however, the next best thing, an annular 

 solar eclipse, will occur as the moon 

 passes in front of the sun without com- 

 pletely covering it. The result wiU be a 

 brilliant ring of sunlight surrounding the 



black disk of the moon. Starting in the Pa- 

 cific Ocean, south of the Hawaiian Islands, 

 the annularity will be visible along a 150- 

 mile-wide swath, extending across the 

 United States, from New Mexico to 

 Maine, before it crosses the Atlantic and 

 ends in Morocco. 



Solar eclipses can occur only during the 

 new moon, the only time of the month that 

 the moon and the sun are in the same part 

 of the sky. Solar eclipses do not occur 

 every month because the orbits of the 

 earth, moon, and sun are not in the same 



plane. The moon's orbit is tilted by 5° in 

 relation to the earth's orbit around the sun, 

 so during the new moon phase, the moon 

 is usually slightly above or below the sun. 

 Only rarely does it pass directly in front of 

 the sun. A minimum of two solar eclipses 

 (total, annular, or partial) occur every 

 year; the maximum is five. 



A further complication is that the 

 moon's orbit is not perfectly round. When 

 the moon is near perigee, its closest dis- 

 tance to the earth, its disk is just large 

 enough to cover the entire sun. (By coinci- 



The times given represent the moment of maximum eclipse and are shown in eastern daylight time (adjust for local time). 



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