Bright spots of sunlight seen around the edge
of the Moon for a few seconds immediately
before and after a total eclipse of the Sun,
caused by sunlight shining between mountains
at the Moon's edge.
Sometimes one bead is much brighter than the
others, producing the so-called diamond ring
effect. The effect was described 1836 by the
English astronomer Francis Baily (1774-1844),
a wealthy stockbroker who retired in 1825 to
devote himself to astronomy.