George Ellery Hale built his first telescope when he was 14 years old. And just a decade later, as a young astronomer at the University of Chicago, he saw a chance to build one of the largest telescopes in the world. It became the centerpiece of Yerkes Observatory, on the shore of Lake Geneva in Wisconsin, which was dedicated 125 years ago today.

The observatory was named for Charles Yerkes, a shady businessman who controlled the Chicago subways.

The telescope was a 40-inch refractor, which focuses light with lenses. Astronomers used it to help establish the new field of astrophysics — analyzing what makes stars and other objects tick. They studied binary star systems, how stars evolve, the dust and gas between the stars, and much more.

In 1932, Chicago and the University of Texas joined forces to establish McDonald Observatory, with the Yerkes director overseeing both of them. The partnership lasted until the 1960s.

Viewing conditions at Yerkes weren’t always the best. And by the 21st century, the 40-inch telescope couldn’t compete with more modern facilities. So Chicago closed the observatory in 2018, then sold it — although it kept its collection of 170,000 photographic plates.

The new owners reopened the site this year for tours, outreach programs, and special events — providing access to one of the most important observatories of the 20th century.
 

Script by Damond Benningfield