False-color emphasizes the structure of the outer solar corona as seen from Skylab in 1973
Skylab image-processed coronagraph photo showing the solar corona, the Sun’s outer atmosphere of hot gases that surrounds the photosphere, the Sun’s surface. The coronagraph blocks the light from the photosphere, allowing the usually invisible, fainter corona to be studied. The central black disc denotes the photosphere. The coronagraph essentially mimics the conditions which prevail during a solar eclipse, when light from the photosphere is obscured by the Moon, allowing the corona to become visible.