Alvan Clark

Who was Alvan Clark?

Alvan Clark, born in Ashfield, Massachusetts, the descendant of a Cape Cod whaling family of English ancestry, was an American astronomer and telescope maker. He was a portrait painter and engraver, and at the age of 40 became involved in telescope making. Using glass blanks made by Chance Brothers of Birmingham and Feil-Mantois of Paris, his firm Alvan Clark & Sons ground lenses for refracting telescopes, including the largest in the world at the time: the 18.5-inch at Dearborn Observatory at the Old University of Chicago, the two 26-inch telescopes at the United States Naval Observatory and McCormick Observatory, the 30-inch at Pulkovo Observatory, the 36-inch telescope at Lick Observatory and later the 40-inch at Yerkes Observatory, which remains the largest successful refracting telescope in the world. One of Clark's sons, Alvan Graham Clark, discovered the dim companion of Sirius. His other son was George Bassett Clark; both sons were partners in the firm.