Alvan Graham Clark
|Born||July 10, 1832|
Fall River, Massachusetts
|Died||June 9, 1897 (aged 65)|
|Known for||Sirius B|
On January 31, 1862, while testing a new 18.5-inch (470 mm) aperture great refractor telescope in Cambridgeport, Massachusetts, Clark made the first ever observation of a white dwarf star. This discovery of Sirius B, or affectionately "the Pup", proved an earlier hypotheses (Friedrich Bessel in 1844) that Sirius, the brightest star in the night sky with an apparent magnitude of −1.46, had an unseen companion disturbing its motion. Clark used the largest refracting telescope lens in existence at the time, and the largest telescope in the United States, to observe the magnitude 8 companion.
- "Alvan Clark, Astronomy, Biographies". AllRefer.com. Archived from the original on June 23, 2004.
- The Dearborn Telescope
- Sirius A & B: A Double Star System In The Constellation Canis Major
- Northwestern University Astronomy and Astrophysics – History of Dearborn Observatory
- Look south to see winter's brightest constellations