The Omega Nebula, M17 or NGC6618, in the constellation Sagittarius. M17 is a bright emission nebula excited by young stars, but with lanes of opaque dust; it is also referred to as the Swan Nebula and the Horseshoe Nebula. M17 is about 5700 light-years away and contains about 800 solar masses of material within its 17-light-year diameter. It is also a source of radio emission. M17 is located, along with its neighbor, the Eagle Nebula, M16, in the Sagittarius-Carina spiral arm of our Milky Way galaxy. This image was created from 21 observations made at the Burrell Schmidt telescope (owned by the Warner and Swasey Observatory of the Case Western Reserve University and situated on Kitt Peak in southwest Arizona), in May 1995 and June 1996 during observing experience for the Research Experiences for Undergraduates (REU) program operated at the Kitt Peak National Observatory and supported by the National Science Foundation. Image size 28.8 arc minutes.