Baily's beads

A phenomenon observed during the progress towards a total solar eclipse, just before totality and again just after totality. As the Moon gradually obscures the disc of the Sun, the final thin crescent appears to be broken up into a string of bright beads because the mountains and valleys on the Moon make its limb uneven. The English astronomer Francis Baily (1774-1844) drew attention to the phenomenon at the solar eclipse of 1836.