he returned to Ingolstadt in 1630 and served as rector in Innsbruck in 1637 and Eichstätt in 1646. Johannes Kepler visited Cysat in Ingolstadt, but only one letter of their correspondence, dated February 23, 1621, survives. On November 7, 1631, Cysat was one of the four first observers of a transit of Mercury predicted by Kepler in 1631. Cysat subsequently returned to his hometown of Lucerne, where he died on March 17, 1657. See also List of Jesuit scientists List of Roman Catholic scientist-clerics References Kurt Scheuerer - Materialsammlung zur Geschichte von Ingolstadt: Johann Baptist Cysat Librairie Thomas-Scheler Right Off the Shelf, by Anna Felicity Friedman 1580s births 1657 deaths 17th-century Swiss astronomers Swiss Jesuits 17th-century Swiss mathematicians University of Ingolstadt alumni Academic staff of the University of Ingolstadt 17th-century Jesuits Jesuit scientists