The Lagoon Nebula is a giant interstellar cloud in the constellation Sagittarius. It is classified as an emission nebula and as a H II region. Discovered by Giovanni Hodierna before 1654, it is one of only two star-forming nebulae faintly visible to the naked eye from mid-northern latitudes. Seen with binoculars, it appears as a distinct oval cloudlike patch with a definite core. In the foreground is the open cluster NGC 6530.Photograph: ESO/VPHAS+ team