The Trifid Nebula lies about 8,000 light-years away in the constellation Sagittarius. It also goes by the names Messier 20 (M20) and NGC 6514. This image was made by the 0.8-meter Telescope at McDonald Observatory, with the Prime Focus Corrector instrument. To obtain a color image, three exposures were added together, one made with a red filter, one with a green filter, and one with a blue filter. Credit: Mary Kay Hemenway/AASTRA teacher program/McDonald Observatory.