Explanation:
The Moon almost ruined this photograph.
During late March and early April 1997,
Comet Hale-Bopp
passed nearly in front of the
Andromeda Galaxy.
Here the Great Comet
of 1997 and the
Great Galaxy in Andromeda were
photographed together
on 1997 March 24th.
The problem was the brightness of the
Moon. The Moon was full that night and so bright that long
exposures meant to capture the
tails of Hale-Bopp and the disk of
M31 would capture instead
only moonlight reflected off the Earth's atmosphere.
By the time the Moon would set, this opportunity would be gone.
That's why this picture was taken during a total
lunar eclipse.
