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How did Wisconsin get the largest telescope in the world?

For decades, the largest refracting telescope in the world was located less than a hour south of Milwaukee, attracting scientists from all over the world to the shores of Lake Geneva and the Yerkes Observatory.

In fact, Albert Einstein himself visited the site on a scientific pilgrimage to the U.S. in 1921.


Yerkes Observatory was dedicated in 1897 by the University of Chicago. It was built in William's Bay, Wis., because of the spacious, natural setting and to escape the light pollution of both Milwaukee and Chicago. When it opened, it featured a gigantic retracting domed roof and, of course, a similarly giant telescope.

The original telescope inside the The Yerkes Observatory. Photo credit: Bobby Tanzilo / OnMilwaukee.

"The six-ton, 60-foot telescope sits atop a whopping 43-foot-tall brick base around which sits the elevator platform that could raise and lower to allow astronomers to access the eyepiece, which would sit at different levels depending on the angle of the telescope required to view the desired spot in the heavens," writes Bobby Tanzilo in his story published at OnMilwaukee.

The main telescope still stands, as well as two smaller ones still in use today under under robotic control. The observatory closed to the public in 2018 and is no longer affiliated with the University of Chicago, but scientists can still use and adjust the smaller telescopes from afar and download images based on precise coordinates.

A view from the outside. Notice the three domed roofs. Photo credit: Bobby Tanzilo / OnMilwaukee.

So why are we talking about the Yerkes Observatory now?

There's a bright future in store for the space, as indicated by the name of its new owner: The Yerkes Future Foundation. Soon to reopen as an event space, museum and public attraction, the observatory will invite a new generation of curious visitors.

Learn about the next chapter, plus much more about the history and discoveries inside in our podcast episode below. And be sure to visit OnMilwaukee for even more photos and history.

Director of Digital Content | Radio Milwaukee