Comet Holmes was discovered in 1892 by Edwin Holmes,
an amateur astronomer in England. The comet's 7-year
orbit lies completely between the orbits of Mars and
Jupiter, and so it does not usually get very bright
or spectacular. In fact, for several decades it was
lost, and is seldom anything more than a smudge in the
largest backyard telescopes.

That changed dramatically on October 24, 2007. For a
reason not yet determined, the comet became over a million
times brighter in less than a day, and was easily visible
to the unaided eye even in large cities. This outburst shows
a comet unlike any other: a bright, small nucleus, surrounded
by a core of dust and gas that within a few days became larger
in diameter than the orbit of the moon around the earth. The
tail of gas visible in this image seems so short because it is
pointed almost directly away from the earth.

Image data:
Camera: Canon 350 XT (modified)
Exposure: ISO 800; composite of 20 seconds x 40; 1 minute x 20; 5 minutes x 10
Telescope: 10" Schmidt-Newtonian, Baader coma corrector