The Witch Head Nebula is reflection nebula located 700-1000 light
years away in the long, dim constellation Eridanus. An easier
way to locate it in the sky is to find Rigel, the bright,
blue supergiant star that marks Orion's western foot. The Witch
Head is just in front of that foot. Rigel, in fact, provides
the reflected light that shines from the Witch Head, even
though Rigel is some 100 light years from this cloud of gas and
carbon dust. The dust reflects the blue wavelengths of light more than the
red ones, and so this nebula is blue not so much because Rigel is, but
because of how dust refelcts (the same dynamic makes the daytime sky on Earth
blue). Rigel is located about one photo-height below this image.
The Witch Head nebula is longer than 5 full moons lined up in the sky, but is
far too dim for human eyes to see. The radiation from very energetic stars
in the Orion region is eroding and sculpting the edge of the nebula so that
it actually looks like its name; in this image, the witch is facing down,
toward Rigel, with her chin at the bottom left. There are also hints of red
in the cloud, which is the result of stellar radiation exciting hydrogen
atoms in the nebula.

Image Data:
Camera: Canon 350 XT (modified)
Telescope: William Optics 66mm + 0.8x reducer / field flattener
Exposure: ISO 800, 5 minutes x 42