science · 03 May 1657 · 367 years ago
death
Died 3 May 1657 (born 1586).
Johann Baptist Cysat, Jean-Baptiste Cysat in French or Latinized as Cysatus was a Swiss astronomer who entered the Jesuit order (1604), and by 1611 was studying at the Jesuit college in Ingolstadt, Bavaria, under Christoph Scheiner, whom he assisted in the observation of sunspots. From 1618, he taught mathematics there. As an early user of a telescope, he was the first to make substantial telescopic observation of a comet (1 Dec 1618 to 22 Jan 1619), Although he discovered the Orion Nebula independently (1619), it had been first noted by Peiresc in 1610. Cysat wrote to Kepler describing a lunar eclipse (1620) and observed the transit of Mercury (1631). It is the comet study for which Cysat is noted. His measurements of its position were made using a 6-foot radius wooden sextant. He published his data and analysis in an 80-page booklet, Mathemata astronomica de locu...cometae... (1619).
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