Johann Baptist Cysatus (1588 - March 3, 1657)

Johann Baptist Cysat (latinized Cysatus) was born in Lucerne, Switzerland in 1588 or 1586. He became Jesuit astronomer and student of Christoph Scheiner (1575-1650) in Ingolstadt, Germany. In 1611, with a telescope, Scheiner and Cysatus started observing sunspots, which they discovered independently from others (in particular Galileo), stimulated by a publication of Kepler. In 1616 or 1618, Cysatus succeeded Scheiner as professor of mathematics and astronomy. From 1623-7 he was Rector of the Jesuit College at Lucerne. 1627-8 he was sent to Spain, and in the 1630s, architect of the Jesuit church in Innsbruck. 1637-41 he chaired the Jesuit College in Innsbruck, 1646-50 the Jesuit College in Eichstätt. He later returned to Lucerne where he died in 1657.

Cysatus was honored by naming a Lunar Crater after him (66.2S, 6.1W, 48.0 km diameter, in 1935).

Cysatus independently discovered the Orion Nebula M42 in 1611, one year after its original discovery by Peiresc. He published these observations in 1619, in his Mathematica astronomica de cometa anni 1618 (Cysatus 1619). Nevertheless, this publication and discovery fell forgotten until their rediscovery by R. Wolf (1854); also see G. Bigourdan (1916).

Other observations include the Mercury transit of September 7, 1631.



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