The 40-inch telescope lens at the Yerkes Observatory remains the largest successful refracting telescope in the world, a feat of engineering attributed to the firm Alvan Clark & Sons. Born in Ashfield in 1804, Clark spent his early career as a portrait painter and engraver before transitioning to the precision manufacture of astronomical instruments in his later years.
Transition from Fine Art to Optics
During the 1830s through the 1850s, Clark established himself as a portrait painter. His artistic background informed his meticulous approach to optics. At age 40, he shifted his focus toward telescope construction. Working from the United States, he sourced glass blanks from manufacturers such as Chance Brothers in Birmingham and Feil-Mantois in Paris to grind high-precision lenses for refracting telescopes.
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The firm Alvan Clark & Sons produced several of the largest lenses of the 19th century. Notable projects include an 18.5-inch lens for the Dearborn Observatory and two 26-inch telescopes for the United States Naval Observatory and McCormick Observatory. Further installations included a 30-inch lens for the Pulkovo Observatory and a 36-inch lens for the Lick Observatory. Beyond professional glassmaking, Clark discovered stellar phenomena, including Mu Herculis, 8 Sextantis, and 95 Ceti, during the testing of his own equipment.
Patents and Recognition
Clark maintained a diverse range of interests, including competitive target shooting. On April 24, 1840, he secured patent 1,565 for a device designed to seat bullets into muzzle-loading rifles without causing damage to the firearm or the ammunition. His contributions to science were formally recognized with the Lalande Prize in 1862 and the Rumford Prize in 1866. He was also elected as a member of the American Academy of Arts and Sciences and the American Philosophical Society in 1880.
Fast facts
- Born: 1804, Ashfield
- Died: 1887, Cambridge
- Citizenship: United States
- Occupations: Astronomer, businessperson, painter, optician
- Awards: Lalande Prize (1862), Rumford Prize (1866)
- Notable Works: Yerkes Observatory, Alvan Clark & Sons
- Member: American Academy of Arts and Sciences
- Burial: Mount Auburn Cemetery
Questions readers ask
Did Alvan Clark work alone?
No, he established the firm Alvan Clark & Sons, which included his sons Alvan Graham Clark and George Bassett Clark as partners.
What happened to the telescope lens at Pulkovo Observatory?
The 30-inch telescope was destroyed during the Siege of Leningrad, though the lens itself survived.
Achievements
- Lalande Prize — 1862
- Rumford Prize — 1866
- Notable work: Yerkes Observatory
- Notable work: Alvan Clark & Sons
