(1804–87) American optician. His company at Cambridge, Massachusetts, made the lenses for the world's two largest refractors, the 36-inch (0.91-m) at Lick Observatory and the 40-inch (1.01-m) of Yerkes Observatory. In 1862 his son Alvan Graham Clark (1832–97) discovered the first white dwarf, the companion of Sirius, while testing an 18½-inch (0.47-m) Clark refractor.
From A Dictionary of Astronomy in Oxford Reference.
Subjects: Astronomy and Astrophysics.