Discovered by Charles Messier in 1764, M20 is a star-forming nebula located 9,000 light-years away from Earth in the constellation Sagittarius. Also known as the Trifid Nebula, M20 has an apparent magnitude of 6.3 and can be spotted with a small telescope. It is best observed during August.

This eerie Hubble image features the center of the Trifid Nebula and the three wing-like bands of thick dust for which the nebula was named. A group of recently formed, massive, bright stars toward the center of the nebula is easily visible. These stars are releasing a flood of ultraviolet radiation that dramatically influences the structure and evolution of the surrounding nebula. Star formation is no longer occurring in the immediate vicinity of this group of bright stars because their intense radiation has blown away the gas and dust from which new stars are made.