Eclipse of the Sun, 7 August 1869.
© Science Museum / Science & Society Picture Library
Lithographic colour print isued by Harvard College Observatory in 1876, showing the corona around the Sun during a solar eclipse. The pearly and ghostly light is only seen during the brief period of totality when the Moon blocks the dazzlingly bright surface of the Sun. The corona forms the outer and very tenuous atmosphere of the Sun, an envelope of highly ionised gas, superheated to over a million degrees centigrade. Etienne Leopold Trouvelot (1827-1895), a French artist, made these sketches during the solar eclipse of 7 August 1869 from Shelbyville, Kentucky in the United States.