This is a color composite image made by Karen Gloria at
Hopkins Observatory using a 6-inch refractor and a 512x512
element CCD detector.  M16 is a young stellar cluster where
the radiation of hot stars causes the surrounding hydrogen
gas to become ionized.  When the electrons and protons recombine
a red emission line is given off.  The blue nebulosity in
this image is associated with preferential scattering of
blue light by dust.  M16 has an overall angular size of approximately
1/2 a degree.