Title:[1068] Omega Nebula (Messier 17) Caption:An infrared color picture of Messier 17, a region of massive star formation located in our Galaxy (the Milky Way) about 7,000 light years from Earth. The color in this infrared picture results from a process in which three images taken through filters at three different wavelengths are combined, similar to the method used by color television. Here the blue, green and red components of the composite represent wavelengths of 1.2, 1.65 and 2.2 microns respectively. The total amount of energy radiated by the stars in Messier 17 is about six million times greater than that radiated by our own Sun. Kitt Peak National Observatory 2.1-meter telescope photo by Ian Gatley, photo made1989. Copyright: Credit:National Optical Astronomy Observatories/Dr. Ian Gatley

Title:[1119] Omega Nebula in Sagittarius Caption:M17, Omega Nebula, Swan Nebula, NGC 6618, in the constellation Sagittarius. A bright nebula with clouds and lanes of opaque dust and gas, M17 is estimated to have a mass 800 times that of our Sun within its 17-light year diameter. This 5,700 light year-distant nebula is a source of radio noise. Kitt Peak National Observatory 4-meter Mayall telescope photo. Copyright: Credit:National Optical Astronomy Observatories

Title:[0052] The Milky Way south of Messier 17 Caption:The French astronomer Charles Messier (1730-1817) listed over 100 objects he saw as nebulous to avoid confusing them with comets, which were his main interest. Three of Messier's objects appear in this picture. A little below the bright red emission nebula M17 is M18, a group of stars which is only conspicuous because, like M17, it is set in a relatively dark region of the Milky Way. The rich cloud of stars more or less in the middle of the photograph was listed by Messier as number 24 in his catalogue and it contains the open cluster NGC 6603, while towards the bottom of this field is a small group of nebulosities that Messier either did not see or which he considered to be too faint to interfere with his comet seeking. These are the two blue reflection nebulae NGC 6589-90 and the emission nebulae IC 1283-4. Copyright:(c) 1987 Royal Observatory Edinburgh Credit:D. F. Malin