The Lagoon Nebula, M8 (NGC 6523)

The Lagoon Nebula, Messier object 8 (M8) or NGC 6523, in the constellation of Sagittarius, as seen by the Kitt Peak 4-meter Mayall telescope in 1973. North is at the top. The lagoon nebula glows with the red light of hydrogen (H alpha) excited by the radiation of very hot stars buried within its center. Deep within the cloud, dark filaments of obscuring matter emit strong infrared radiation. Several peculiar variable stars in the nebula occasionally flare up, increasing in brightness to some 25 times their normal luminosity. The nebula is about 6500 light-years away and about 60 light-years across.