Polar caps and Syrtis Major

Polar caps and Syrtis Major

. The English amateur astronomer Warren De La Rue (1815-1889) made this drawing of Mars on 20 April 1856, using a 0.33-meter (13-inch) reflector telescope. It shows bright polar caps and a dark, triangular feature now known as Syrtis Major Planitia (Gulf of Sirte Plains). The Dutch astronomer Christiaan Huygens (1629-1695) first sketched this feature in 1659. From his observations of Syrtis Major, Huygens concluded that the rotation period of Mars is about 24 hours. This drawing is reproduced from Camille Flammarion’s 1892 book La Planete Mars et ses Conditions d’Habitabilité.

Copyright 2010, Professor Kenneth R. Lang, Tufts University