Cassegrain, Laurent

Bornnear Chartres, (Eure-et-Loir), France, circa1629

Died Chaudon, (Eure-et-Loir), France, 31 August 1693

The name of Cassegrain is associated with the optical configuration of the so called Cassegrain telescope, the type most widely used in the world. However, the man who gave his name to this reflecting telescope had not been clearly identified before 1997. Laurent Cassegrain was the son of Mathurin Cassegrain, a grocer and haberdasher in the town of Chartres, and Jehanne Marquet. Although Cassegrain’s birth certificate has not yet been found, we know that Laurent had at least five brothers and sisters, who were born and baptized in Chartres between 1631 and 1646. According to the age indicated in his death certificate, Laurent was born between 1628 and 1630, at a time when the plague was raging in France. While a number of Cassegrain’s relatives were surgeons in Chartres, nothing is known of the education of Laurent, who is not mentioned in local records before 1654. He is then...