page_title: Yerkes Observatory
section_title: Telescopes
hierarchical_section_title: Yerkes Observatory / Telescopes
caption_attribution_description: Alvan Graham Clark and his assistant Carl Lundin (right) alongside of the 40-inch Lens.
context_page_description: Yerkes Observatory is an astronomical observatory located in Williams Bay, Wisconsin, U.S.A. It was operated by the University of Chicago Department of Astronomy and Astrophysics from its founding in 1897 to 2020. Ownership was transferred to the non-profit Yerkes Future Foundation in May, 2020.
  The observatory, sometimes called "the birthplace of modern astrophysics", was founded in 1892 by astronomer George Ellery Hale and financed by businessman Charles T. Yerkes.
  It represented a shift in the thinking about observatories, from their being mere housing for telescopes and observers, to the early-20th-century concept of observation equipment integrated with laboratory space for physics and chemistry analysis.
  The observatory's main dome houses a 40-inch diameter doublet lens refracting telescope, the largest refractor ever successfully used for astronomy. Two smaller domes house 40 in and 24 in reflecting telescopes. There are several smaller telescopes - some permanently mounted - that are primarily used for educational purposes. The observatory also holds a collection of over 170,000 photographic plates.
context_section_description: In the 1860s Chicago became home of the largest telescope in America, the Dearborn 18 1/2 inch refractor. Later surpassed by the U.S. Naval Observatory's 26 inch, which would go on to discover the moons of Mars in 1877, there was an extraordinary increase of larger telescopes in finely furnished observatories in the late 1800s. In the 1890s various forces came together to establish an observatory of art, science, and superlative instruments in Williams Bay, Wisconsin.
  The telescope was surpassed by the Harvard College Observatory, 60 inch reflector less than ten years later, although it remained a center for research for decades afterwards. In addition to the large refractor, Yerkes also conducted a great amount of Solar observations.
caption: Alvan Clark polishes the big Yerke objective lens in 1896
exif: {}