This summer, darkness will fall across the face of America. Birds will stop singing. Temperatures will drop. Stars will become visible in the daytime sky. In about 100 days, a total solar eclipse will sweep across the continental United States for the first time since 1918. Astronomers are calling it the Great American Eclipse.

For the amateur sky-watcher, a total eclipse presents a rare opportunity to witness a cosmic hiccup in our day-night cycle. For solar astronomers, however, the eclipse offers something else: three minutes (give or take) to collect as much data as possible about the sun’s usually hidden outer atmosphere. Researchers have been anticipating the event for years. FULL REPORT