Yerkes Observatory: The Largest Refracting Telescope Ever Built
Near Lake Geneva, Wisconsin
On the southeastern shore of Geneva Lake, in the small village of Williams Bay, stands the largest refracting telescope ever successfully used for astronomical research. This is the Yerkes Observatory, and when it opened in eighteen ninety-seven it represented the cutting edge of how humans studied the sky. It was founded by astronomer George Ellery Hale and financed by Chicago streetcar magnate Charles T.
Yerkes, who paid for the telescope and the building in exchange for having his name attached to both. The main lens is forty inches in diameter, and no refracting telescope larger than this has ever been put to successful use. The building that houses it was designed by architect Henry Ives Cobb in the Romanesque Revival style, and the grounds were landscaped by John Charles Olmsted, nephew of Frederick Law Olmsted, the designer of Central Park in New York.
For decades the University of Chicago operated the observatory, and research conducted there helped shape modern astrophysics. Edwin Hubble worked at Yerkes as a graduate assistant before going on to his transformative work at Mount Wilson Observatory in California. The University of Chicago closed the observatory in October of twenty eighteen after more than a century of operation.
A nonprofit organization called the Yerkes Future Foundation took ownership, and the facility reopened for public tours and educational programming in May of twenty twenty-two. The forty-inch telescope still works. Visitors who time their trip right can look through the same eyepiece that astronomers have used for more than a century to map the universe.
