The NSF NCAR Mesa Lab and Fleischmann buildings will be closed on Monday, Dec. 23, due to nearby water leak.

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The Sun, the Moon, and us: A guide to the Great American Eclipse of 2017

A solar eclipse occurs when the Moon passes between the Sun and Earth, causing the Moon to block the light from the Sun. Typically the Moon only partially blocks the Sun’s light during an eclipse, however occasionally the Moon completely blocks the Sun, causing what is called a total solar eclipse. August 21, 2017, will be just one of those occasions: the first in the continental United States since 1979. For many people across the U.S. who are under the "path of totality," day will turn to night for two minutes during this time and the Sun’s enigmatic faint extended atmosphere, or “corona,” will shine in the dark sky. Learn about this unique event: How it happens, where to view it, how to view it safely, and what you can expect from it!