Lagoon Nebula

Messier 8 (NGC 6523), the Lagoon Nebula, is a sweeping emission nebula and star-forming region in the constellation Sagittarius, lying approximately 6,500 light-years from Earth and spanning about 60 light-years across. It was first recorded by Giovanni Battista Hodierna before 1654, and Guillaume Le Gentil independently observed it in 1747; Charles Messier catalogued it in 1764. The Lagoon's distinctive structure — a glowing cloud bisected by a dark dust lane that early observers likened to a lagoon or tidal inlet — is visible to the naked eye from a dark site as a fuzzy patch in the Milky Way, and becomes a spectacular sight in binoculars or a telescope.

NGC 6523 glows with the characteristic red light of hydrogen energized by ultraviolet radiation from a handful of intensely hot, young stars buried within its center. Deep inside the brightest knot of the nebula, known as the Hourglass Region, powerful stellar winds sculpt dark filaments and pillars of dust that emit strongly in the infrared — sites where new stars may be condensing even now. Several peculiar variable stars within the nebula occasionally flare to roughly 25 times their normal brightness, and the embedded open cluster NGC 6530 contains dozens of hot blue stars that formed from this cloud within the past few million years.

The Lagoon is one of only two star-forming nebulae visible to the unaided eye from northern latitudes (the other is the Orion Nebula), and it rewards any aperture. This image was captured at the Kitt Peak National Observatory 4-meter Mayall telescope in 1973, with north at the top.