Cool. This reminds me, obliquely, of the fact that there is much
more going on in the apparently familiar sky than we can easily see.
Distant planetary nebulae are easy to photograph because they are
compact, and you can easily get a long exposure that scoops up their
light, but something nearer would be more dispersed, and harder to
notice. Thus, you shouldn't be too surprised to learn what you find
when you collect several nights' worth of light looking at the
familiar constellation Orion:
http://primefocus.tumblr.com/post/1980839861/orion-is-one-of-the-most-familiar-constellationsAbout 1000ly away, a lot of galactic history in that part of the sky.
Buried in all the nebular light in the centre there is Orion's belt and
sword, the whole image is some 20 degrees or so across. I think I worked
out once that the nebular ring is about 15 degree diameter (the moon is
1/2 degree).
