"We are lucky to live in a solar system where the sun and moon appear the same size
in the sky. This remarkable coincidence leads to one of nature's most awesome
spectacles, a total solar eclipse of the sun, when the sun, moon, and earth are almost
perfectly aligned so that the moon completely blocks the sun's disk for as long as
several minutes. Each of our lifetimes is measured by only a small number of total
solar eclipses, during which the sun's disc is totally hidden.

The most fleeting phase of a total solar eclipse is the beautiful "diamond ring"
phase. For ~1 second before and after totality, when a miniscule bit of sunlight shines
through the valleys on the limb of the moon, the exlipsed sun takes on the appearance of
a celestial gem, the "diamond ring." The best diamond rings appear when sunlight
filters through the moon's deepest valleys; sometimes no diamond ring appears.

During the total eclipse on July 11, 1991, the sun was hidden behind the moon for
~4 minutes for observers in Hawaii. As totality ended at 7:32 am, the sun emerged
from behind the moon at just the location of particularly deep valleys on the
western limb of the moon, as shown below, giving rise to an unusually beautiful
diamond ring. The diamond ring captured here was photographed from Hapuna Beach,
on the Big Island of Hawaii the morning of July 11, 1991, by Nick Devereux (who
clicked the shutter) and Judy Yound (who set up the exposure). Using a Pentax K1000
with a 210 mm zoom lens and a tripod, Fujichrome film ASA 100 was exposed for 1/60
sec. at f/8. The clouds which covered the sky during the eclipse became illuminated
by the diamond."