Baily's Beads

This image highlights Baily's Beads, a feature of total solar eclipses that are visible at the very beginning and the very end of totality. It's composed of a series of images taken during a total solar eclipse visible from ESO's La Silla Observatory on 2 July 2019.

Baily's Beads are caused by the Moon's mountains, valleys, and craters. These surface features create an uneven edge of the Moon, where small "beads" of sunlight still shine through the lowest parts for a few moments after the rest of the Sun is covered. In this picture, multiple images taken in quick succession show that the beads disappear and appear in stages, with only the very deepest valley and craters allowing the sunlight to shine through closest to totality. The phenomenon is named after Francis Baily, a British astronomer whose observations in the early 1800s first widely publicised their existence. Appropriately, 2019 was the 245th anniversary of Baily's birth.