Alvan Graham Clark

Alvan Graham Clark was an American astronomer and lens manufacturer who is best known for his role in the discovery of Sirius B. In 1857, he founded the Alvan Clark & Sons company in Cambridge, Massachusetts, which specialized in the manufacture of telescopes and scientific instruments. Clark’s telescopes quickly gained a reputation for their exceptional quality and accuracy, and the company became one of the leading manufacturers of telescopes in the United States.

Some key dates in Clark’s career as a telescope manufacturer include:

The world’s largest refractor telescope, the 26-inch (66-cm) aperture “Great Equatorial” designed and built by the firm of Alvan Clark & Sons of Cambridge, Massachusetts and delivered on Nov. 12, 1873

1857: Alvan Graham Clark founds the Alvan Clark & Sons company.
1862: Alvan Graham Clark and his son William discover Sirius B while observing through one of the telescopes they manufactured.
1872: The U.S. Naval Observatory orders its first Alvan Clark & Sons telescope.
1873: The company moves to its current location in nearby Greenwood, Massachusetts.
1879: The Alvan Clark & Sons company produces the largest refracting telescope in the world, which was installed at the United States Naval Observatory in Washington, D.C.
Clark’s legacy as a manufacturer of high-quality telescopes continues to this day, and many of his telescopes are still in use in observatories around the world.