[Friends_of_SSASTROS] Cassegrain

[LOUIS GENTILE]

Today is the anniversary of the death, at Chaudon on 1 Sep 1693 (some sources state 31 Aug), of the French Catholic priest and instrument maker Laurent Cassegrain. Although no verifiable portrait of him is known to exist. Born at Chartres in around 1629, he is best known to astronomers as being the probable inventor of a type of reflecting telescope which uses a combination of a primary concave mirror and a secondary convex mirror. Now known as the Cassegrain reflector, Cassegrain’s design first appeared in the 25 Apr 1672 issue (pictured) of Le Journal des Sçavans (established by French writer Denis de Sallo in 1665 and the earliest academic journal published in Europe).


Louis A. Gentile 

Cell    781-561-5535