Alvan Clark & Sons
Alvan Clark & Sons was an American maker of optics that became famous for crafting lenses for some of the largest refracting telescopes of the 19th and early 20th centuries. Founded in 1846 in Cambridgeport, Massachusetts, by Alvan Clark, and his sons George Bassett Clark and Alvan Graham Clark. Five times, the firm built the largest refracting telescopes in the world. The Clark firm gained "worldwide fame and distribution", wrote one author on astronomy in 1899.
The Dearborn telescope was commissioned in 1856 by the University of Mississippi. The outbreak of civil war prevented them from ever taking ownership. As a result, it was being tested in Cambridgeport when Alvan Graham observed Sirius B in 1862.
In 1873 they built the objective lens for the refractor at the United States Naval Observatory. In 1883, they build the telescope for the Pulkovo Observatory in Russia, the objective for the refractor at Lick Observatory was made in 1887, and the lens for the Yerkes Observatory refractor, in 1897, only ever exceeded in size by the lens made for Great Paris Exhibition Telescope of 1900.
The company also built a number of smaller instruments, which are still highly prized among collectors and amateur astronomers.
The company's assets were acquired by the Sprague-Hathaway Manufacturing Company in 1933, but continued to operate under the Clark name. In 1936, Sprague-Hathaway moved the Clark shop to a new location in West Somerville, Massachusetts, where manufacturing continued in association with the Perkin-Elmer Corporation, another maker of precision instruments. Most of Clark's equipment was disposed of as scrap during World War II, and Sprague-Hathaway itself was liquidated in 1958.
