M17 "Omega / Swan" Nebula
Serpens-Sagittarius-Scutum Boundary

This image covers a rectangle of sky approximately 3 x 5 degrees. Photographic film and CCD cameras reveal huge areas of hydrogen-alpha (red) emission. These clouds of stars and gas are situated in the Sagittarius and Scutum-Crux arms of the Milky Way a few degrees from the direction of the galactic core. Visual observation, even with a large telescope reveals little color because the human eye is quite insensitive to red light.