Stars in Their Eyes

The exquisite telescopes crafted by Alvan Clark and his sons helped make the last half of the 19th century a golden age of astronomy

  • By Michael Tennesen
  • Smithsonian magazine, October 2001, Subscribe
 

  Alvan Clark didn't know anything about telescopes when, in 1844, his son George made one out of the melted-down brass of his school's broken dinner bell. But the elder Clark was soon hooked on a new hobby, one at which the established portrait painter apparently excelled. He began making refractor telescopes—which use paired lenses to focus light—and taught himself to be a master optician, able to spot even the tiniest imperfections in the glass objectives he crafted.

His two sons, George Bassett Clark and Alvan Graham Clark, joined their father's growing business, and together they founded the firm of Alvan Clark and Sons, makers of the finest—and largest—refractor telescopes of their time. Before they were done, the Clarks had five times created lenses for the world's largest telescopes, often beating their own records.

Through Clark telescopes, scientists have discovered the spiral arms of our own galaxy, the moons of Mars, the fifth moon of Jupiter. The first evidence of an expanding universe, the observation that other galaxies are moving away from us, was found with a Clark refractor.

Today, refractors have been largely eclipsed for research use by reflector telescopes. (Barrel-shaped as opposed to long and lean, these telescopes use mirrors to focus light.) But the Clark refractors—from the 40-inch at the Yerkes Observatory (the world's largest, completed months before the youngest Clark's death in 1897) to the hundreds of smaller models, cherished by collectors—remain elegant reminders of a golden age of astronomy, and one family's dedication to its craft.


  Alvan Clark didn't know anything about telescopes when, in 1844, his son George made one out of the melted-down brass of his school's broken dinner bell. But the elder Clark was soon hooked on a new hobby, one at which the established portrait painter apparently excelled. He began making refractor telescopes—which use paired lenses to focus light—and taught himself to be a master optician, able to spot even the tiniest imperfections in the glass objectives he crafted.

His two sons, George Bassett Clark and Alvan Graham Clark, joined their father's growing business, and together they founded the firm of Alvan Clark and Sons, makers of the finest—and largest—refractor telescopes of their time. Before they were done, the Clarks had five times created lenses for the world's largest telescopes, often beating their own records.

Through Clark telescopes, scientists have discovered the spiral arms of our own galaxy, the moons of Mars, the fifth moon of Jupiter. The first evidence of an expanding universe, the observation that other galaxies are moving away from us, was found with a Clark refractor.

Today, refractors have been largely eclipsed for research use by reflector telescopes. (Barrel-shaped as opposed to long and lean, these telescopes use mirrors to focus light.) But the Clark refractors—from the 40-inch at the Yerkes Observatory (the world's largest, completed months before the youngest Clark's death in 1897) to the hundreds of smaller models, cherished by collectors—remain elegant reminders of a golden age of astronomy, and one family's dedication to its craft.

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Comments (3)

I have a telescope that was made by Alvan Clark & Sons Comp of Cambridge, Mass with the metal plate stamped C2020. It is 42 inches long and extends to 52 inches with a 3.5 inch refractor lens and 3 spare eye pieces. It is kept in a wooden box along with the eye pieces but the wooden legs are now missing.

Posted by Clara E White on August 18,2012 | 03:34 PM

Clark telescopes are historically important. There is an excellent book on the subject, 'Alvan Clark and Sons, Artists in Optics', by D. Warner and R. Ariail, that is still in print. Please do not try to clean the optics or restore the telescope, without expert advice. If there is any way you can provide photos of the telescope and the engraving, that would be very helpful. 1856 is early for the Clarks and it would be useful to have a visual confirmation of this engraving. Thank you for preserving this instrument, Peter Abrahams email: abrahams.peter@gmail.com

Posted by Peter Abrahams on April 28,2012 | 04:45 AM

I just recently brought a telescope out of our attic that I have had since I was about 10 (I am now 65). I can remember using is as a child, but really wasn't into finding out much about it's history until now. It is a 4" refractor with brass gears and a wooden tube. It has a wooden tripod and wooden carrying case. The plate that holds the lenses is engraved: Alvan Clark and Sons, Cambridge Mass., 1856. I have multiple lenses in their own case and some kind of extendable "legs" that are in the same case that stores the telescope. I am just now trying to do research and would very much appreciate and direction you could give me.
Thanks,
Dave Stieve

Posted by Dave Stieve on April 17,2012 | 12:39 AM



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