Top row first image: In 1659, the first sketch of Mars was drawn by the Dutch astronomer, Christiaan Huygens. He used a telescope of his own design, which had a magnification of 50 times (much stronger than previous telescopes). He was also the first man to see the white south polar cap of the planet, and he estimated it revolved around the Earth once every 24 hours. Top row second image: Wilhelm Beer and Johann von Maedler (1830) made 35 drawings of Mars with a 200 fold magnification. They determined a rotational period of 24 hours, 37 minutes, 22.6 seconds. Top row third image: Giovanni Schiaparelli (1881) announced the discovery of a network of narrow lines on Mars, which he described as "canali," an Italian word that means "channels." In Italian, the word can mean a natural channel like a river valley. Bottom row: Kasimir Graff (1909) working with a large refractor drew a series of pictures of Mars which bear little trace of canals, but there is an eccentrically rotating south pole.