Martin van den Hove

Martin van den Hove, called Maarten in Dutch and known in Latin as Martinus Hortensius or Ortensius, was a Dutch astronomer and mathematician who lived from 1605 to 7 August 1639. Born in Delft, he studied at Leiden University under Snellius and Isaac Beeckman and from 1628 became a pupil and enthusiastic supporter of the aged Copernican astronomer Philippe van Lansberge, whose Commentationes on the motion of the earth he translated into Latin in 1630 and defended against Tycho Brahe. At the encouragement of Gerard Vossius and Caspar Barlaeus he began lecturing on the mathematical sciences at the Amsterdam Athenaeum Illustre in 1634, opening with an inaugural speech on the dignity and utility of mathematics, and later lectured on optics and navigation. He devised a method of measuring the diameters of planets from the visual angle seen in his telescope, corresponded with Descartes, Mersenne, Gassendi, Huygens and Galileo, and was named to the 1638 commission discussing longitude with Galileo. He died in 1639 soon after being nominated professor at Leiden, and the lunar crater Hortensius bears his name.