Credits: ESA / Hubble & NASA
M18 is a relatively dim open star cluster located in the constellation Sagittarius.
The cluster lies at an approximate distance of 4,900 light years, or 1,500 parsecs, from Earth and has an apparent magnitude of 7.5. Its designation in the New General Catalogue is NGC 6613.
Messier 18 may form a binary star cluster with the nearby NGC 6618, embedded within Messier 17(the Omega Nebula). Scientists have speculated that the proximity of the two clusters may suggest that they had formed together.
Messier 18 is one of Charles Messier’s original discoveries.
Facts about M18 by Keith Turnecliff
M18 is an open cluster of stars in the constellation Sagittarius. It was discovered by Charles Messier in 1764 and included in his list of comet-like objects. From the perspective of Earth, M18 is situated between the Omega Nebula (M17) and the Sagittarius Star Cloud (M24).