The Lagoon Nebula a giant interstellar cloud in the constellation Sagittarius. It is classified as an emission nebula and has an H II region. The Lagoon Nebula was discovered by Giovanni Hodierna in 1654 and is one of only two star-forming nebulae faintly visible to the eye in clear skies. Seen with binoculars, it appears as a distinct cloud-like patch with a definite core. Within the nebula is the open cluster NGC 6530.
