斯皮策望远镜的三叶星云
2020 February 13 Spitzer’s Trifid Image Credit: J. Rho (SSC/Caltech), JPL-Caltech, NASA Explanation: The Trifid Nebula, also known as Messier 20, is easy to find with a small telescope. About 30 light-years across and 5,500 light-years distant it’s a popular stop for cosmic tourists in the nebula rich constellation Sagittarius. As its name sugges...