Partial — and Annular — Eclipse of the Sun
People with clear skies across most of the U.S., Canada, and Mexico will experience a partial eclipse of the Sun late this Sunday afternoon (May 20, 2012). Only those near the Eastern Seaboard will miss out.
And, if you happen to be in a swath of land running from Northern California to Texas, you’ll also get a very special kind of partial eclipse: an annular eclipse, in which the rim of the Sun becomes a brilliant ring completely encircling the black silhouette of the Moon.
The Sun will be moving down the afternoon sky when a dark dent begins to intrude into one edge. The dent will deepen, eventually turning the Sun into a fat crescent — or, for western half of the continent, a thin crescent. The dent is the silhouette of the new Moon traveling along its monthly orbit around the Earth.
Most Westerners can see the entire eclipse from beginning to end before sunset. Farther east, sunset puts an end to the show while the eclipse is still in progress — affording weird and spectacular sunset scenes just above the west-northwest horizon. “This is going to be a great photo opportunity,” suggests Robert Naeye, editor in chief of Sky & Telescope magazine.
