The Iris Nebula
Sep 06, 2010
Last night I took this picture of the Iris Nebula (NGC 7023) with my 10
inch reflector telescope and my CCD camera. The blue light is
starlight from the bright central star that has reflected off from the
interstellar dust. The dust reflects blue light more than other colors.
The reason is the same as why our daytime sky is blue. Anyway, such
nebulae are called reflection nebulae.
  --Bob