| Alvan Graham Clark | |
|---|---|
Alvan Clark and his assistant Carl Ludin (right) alongside of the 40-inch lens, 1896.
|
|
| Born | July 10, 1832 Fall River, Massachusetts |
| Died | June 9, 1897 (aged 64) |
| Nationality | American |
| Fields | Astronomy |
| Known for | Sirius B |
Alvan Graham Clark (July 10, 1832 – June 9, 1897), born in Fall River, Massachusetts, was an American astronomer and telescope-maker. He was the son of Alvan Clark, founder of Alvan Clark & Sons.
On January 31, 1862, while testing a new 18½ inch refracting telescope, he made the first observation of Sirius B in Cambridgeport, Massachusetts. The magnitude 8 companion of Sirius is also the first known white dwarf star.
The 18½ inch refracting telescope is now still being used at the landmark Dearborn Observatory of Northwestern University in Evanston, Illinois.[1]