Claude-Siméon Passemant
1702-1769
Passement was born in 1702. He tried a number of trades before settling on instrument making. After studying at the Collége Mazarin, Passemant failed at law before turning to haberdashery. He married at age 31 and turned the business over to his wife so that he could devote himself to astronomy, precision instrumentation, and optics. He published a treatise on the manufacture of a reflecting telescope in 1738. After presentation of an award-winning, astronomical clock to Louis XV in about 1749, he was named "Ingenieur du Roy" (an official instrument maker to the king), and was given a pension and place to live at the Louvre in Paris.
Passemant is known for fine reflecting telescopes, microscopes, clocks, and other instruments. His own astronomical instruments included a transit (of 33-inch focal length) and a reflecting telescope (of 30-inch focal length). He successfully applied a clock drive to a large telescope he produced for the king in 1757.
Passemant is known for fine reflecting telescopes, microscopes, clocks, and other instruments. His own astronomical instruments included a transit (of 33-inch focal length) and a reflecting telescope (of 30-inch focal length). He successfully applied a clock drive to a large telescope he produced for the king in 1757.
PASSEMANT, Construction d'un Télescope par réflexion, de Mr. Newton, Ayant seize pouces de longueur, & faisant l'effet d'une lunette de huit pieds, Et de plusieurs autres Télescopes. Avec la composition de la matière des Miroirs, & la manière de les polir & de les monter. On y a joint un Traité de l'Art de faire facilement les grands Verres Objectifs, les Oculaires, & les Lentilles de différens foyers, avec la construction des Lunettes & des Microscopes, & leurs principaux usages (Amsterdam & Leipzig: J. Schreuder & P. Mortier, 1756)