This great cloud of glowing red gas known as the Keyhole or Carinae Nebula (NGC 3372) is located in the constellation Carina in a part of the Milky Way visible only from points south of the Tropic of Cancer. The immense nebula, consisting mainly of hydrogen gas, is one of the most spectacular objects in the Milky Way. Even from a great distance (about 8,000 light years from Earth), it occupies a space in the night sky of the Southern Hemisphere about the size of 16 full Moons.
    The name Keyhole Nebula derives from the dark lanes of gas shaped roughly like a door’s keyhole. These lanes divide the glowing red areas into what appear to be several islands. The gas in the red areas glows because of the  intense radiation emitted by very