distance between the sun and Venus when the latter was visible in the daytime. The Hessian star catalogue was published in Historia coelestis (Augsburg, 1666) by Albert Curtz, and a number of other observations are to be found in Coeli et siderum in eo errantium observationes Hassiacae (Leiden, 1618), edited by Willebrord Snell. R. Wolf, in his Astronomische Mittheilungen, No. 45 (Vierteljahrsschrift der naturforschenden Gesellschaft in Zurich, 1878), has given a resume of the manuscripts still preserved at Kassel, which throw much light on the methods adopted in the observations and reductions. Family and children William was married to Sabine of Württemberg, daughter of Christoph, Duke of Württemberg. They had the following children: Anna Maria of Hesse-Kassel (27 January 156721 November 1626), married on 8 June 1589 to Louis II, Count of Nassau-Weilburg Hedwig of Hesse-Kassel (30 June 15697 July 1644), married on 11 September 1597 to Ernst of Schaumburg Agnes of Hesse-Kassel (30 June 15695 September 1569) Sofie of Hesse-Kassel (10 June 157118 January 1616) Maurice, Landgrave of Hesse-Kassel (25 May 157215 March 1632), succeeded as landgrave on William IV's death in 1592. Sabine of Hesse-Kassel (12 May 157329 November 1573) Sidonie of Hesse-Kassel (29 June 15744 April 1575) Christian of Hesse-Kassel (14 October 15759 November 1578) Elisabeth of Hesse-Kassel (11 May 157725 November 1578) Christine (19 October 157819 August 1658), married on 14 May 1598 to John Ernst, Duke of Saxe-Eisenach Juliane, born and died 9 February 1581 In addition William had a few illegitimate children. Most significant and favored among these was Philipp von Cornberg (1553–1616), William's son by Elisabeth Wallenstein. Philipp was ennobled by his father and became the ancestor of the current Barons von Cornberg. Ancestors References External links Biographical data and references at The Galileo Project |- William 4 16th-century German astronomers Scientists from Kassel People from the Landgraviate of Hesse-Kassel 1532 births 1592 deaths Landgraves of Hesse Hesse-Kassel, William IV, Landgrave of