Created page with "essier 18 or M18 (also designated NGC 6613) is an open cluster of stars in the constellation Sagittarius. It was discovered by Charles Messier in 1764 and included in his ..."
(Created page with "essier 18 or M18 (also designated NGC 6613) is an open cluster of stars in the constellation Sagittarius. It was discovered by Charles Messier in 1764 and included in his ...")