Alvan Clark & Sons
| Company type | Private |
|---|---|
| Industry | Optical manufacturing |
| Founded | 1846 in Cambridgeport, Massachusetts, United States |
| Founder | Alvan Clark, George Bassett Clark, Alvan Graham Clark |
| Fate | Acquired by Sprague-Hathaway Manufacturing Company in 1933; brand discontinued after 1958 |
| Headquarters | Cambridgeport (later West Somerville) , United States |
Area served | International |
| Products | Lenses for refracting telescopes, optical instruments |
| Parent | Sprague-Hathaway Manufacturing Company (from 1933) |
Alvan Clark & Sons was a distinguished American firm specializing in optical manufacturing, acclaimed for crafting lenses used in some of the largest refracting telescopes throughout the 19th and early 20th centuries. Established in 1846 in Cambridgeport, Massachusetts by Alvan Clark (1804–1887) alongside his sons George Bassett Clark (1827–1891) and Alvan Graham Clark (1832–1897), the company was responsible for producing five of the world’s biggest refracting telescopes during its tenure. By the end of the 19th century, it had secured international acclaim and widespread distribution within the astronomical community.
Among their notable projects was the telescope intended for the Dearborn Observatory, commissioned in 1856 by the University of Mississippi; however, delivery was halted due to the Civil War. The telescope underwent testing in Cambridgeport, where in 1862 Alvan Graham Clark made the groundbreaking observation of Sirius B, a milestone in astronomical science.
Significant contributions by the firm include fabricating the objective lens for the United States Naval Observatory in 1873; supplying the lens for Russia’s Pulkovo Observatory in 1883; creating the lens for Lick Observatory in 1887; and producing the lens for Yerkes Observatory in 1897, which ranked among the largest ever constructed, second only to the Great Paris Exhibition Telescope of 1900.
Beyond large-scale lenses, Alvan Clark & Sons also manufactured smaller optical instruments, highly regarded by collectors and amateur astronomers alike.
In 1933, Sprague-Hathaway Manufacturing Company acquired the company's assets but maintained operations under the Clark brand. Three years later, production was moved to West Somerville, Massachusetts, where Sprague-Hathaway collaborated with precision instrument manufacturer PerkinElmer. The majority of Clark’s equipment was dismantled during World War II, and Sprague-Hathaway ceased operations through liquidation in 1958.