Explanation:
Just before the Sun blacks out, something strange occurs.
As the Moon moves to completely cover the Sun in a
total solar
eclipse -- like the
one set to occur over parts of Australia
on Tuesday --
beads of bright sunlight stream
around the edge of the Moon.
This effect, known as
Baily's beads,
is named after
Francis Baily
who called attention to the
phenomenon
in 1836.
Although, the number and brightness of
Baily's beads used to be unpredictable, today the Moon
is so well mapped that general features regarding Baily's beads are expected.
When a single bead dominates, it is called the
diamond ring effect,
and is typically seen just before totality.
Pictured above, horizontally compressed,
a series of images recorded Baily's beads at times
surrounding the 2008 total solar eclipse
visible from
Novosibirsk,
Russia.
At the end of totality, as the Sun again emerges from behind the moon,
Baily's beads
may again be visible -- but now on the other side of the Moon.
