M31:仙女座星系
2019 September 9 M31: The Andromeda Galaxy Image Credit & Copyright: Amir H. Abolfath (TWAN) Explanation: How far can you see? The most distant object easily visible to the unaided eye is M31, the great Andromeda Galaxy, over two million light-years away. Without a telescope, even this immense spiral galaxy appears as an unremarkable, faint, nebulous clo...