1586-1657

Swiss astronomer credited with the first telescopic observations of a comet (1618). Cysat observed the comet of 1618-19 almost continuously for two months, attempting to show the object was supralunary. He proposed two models to explain its motion, both of which assumed a stationary Earth. Cysat also observed the lunar eclipse of 1620, the transit of mercury in 1631, and the Orion Nebula in 1619—which had previously been observed by Peiresc in 1610.