Ritchey was educated as a furniture maker. He coinvented the Ritchey–Chrétien (R–C) reflecting telescope along with Henri Chrétien. The R-C prescription remains the predominant optical design for telescopes and has since been used for the majority of major ground-based and space-based telescopes.
He worked closely with George Ellery Hale, first at Yerkes Observatory and later at Mt. Wilson Observatory. He played a major role in designing the mountings and making the mirrors of the Mt. Wilson 60-inch (1.5 m) and 100-inch (2.5 m) telescopes. Hale and Ritchey had a falling-out in 1919, and Ritchey eventually went to Paris where he promoted the construction of very large telescopes. He returned to America in 1930 and obtained a contract to build a Ritchey-Chrétien telescope for the U.S. Naval Observatory. This last telescope produced by Ritchey remains in operation at the U.S. Naval Observatory Flagstaff Station in Flagstaff, Arizona.
A very readable biography of Ritchey and Hale is in Don Osterbrock's book "Pauper and Prince - Ritchey, Hale and the Big American Telescopes" (The university of Arizona Press, 1993) where the idiosyncratic personalities of both Ritchey and Hale are exposed.
