Yerkes Observatory in the 21st Century

There are a number of observatories around the world that fall into the category of “venerable and still usable”. Think of Mount Wilson and its 100-inch Hooker telescope. Or consider Palomar’s collection of scopes, including the 200-inch Hale. It also showcases the historic Samuel Oschin Telescope, a survey instrument that has produced mind-boggling images of the universe. Then, there are the facilities at Pic du Midi, in England, the observatories in Australia, and South Africa. These (and many others) are places where astronomy’s scientific advances into astrophysics began. And, of course, there’s Yerkes Observatory, one of the most venerated in the U.S. For multiple generations of astronomers, it was among the best places to do their science. They spread out to other observatories to teach their own students and continue the exploration of the universe.

I learned of the Yerkes history when I first visited it in the 1990s. It was a marvelous place to be, a sort of “shrine” to early astrophysics. A year or so back, while doing research for my latest book, I had a chance to dig further into its history, and its future looked very uncertain. That may change soon, for reasons I’ll get to below.

A Nineteenth-century Observatory

Astronomer George Ellery Hale founded Yerkes in 1897. He also played a significant role in the founding and building of other observatories in California, as well. The late nineteenth century was just about the time astronomy began to embrace the astrophysical side of things. Through the succeeding hundred years, astronomers from around the world used Yerkes as a training ground and research center. This included my own grad school advisor John C. Brandt, such folks as Carl Sagan, E.E. Barnard, Gerard Kuiper, and many others. It has also been a noted center for astronomy educators to learn their trade.

Yerkes is the birthplace of modern astrophysics. Work done there forms a basic underpinning to much of astrophysics. That includes the development of a spectral classification method called the MKK system (named after astronomers William Wilson Morgan, Philip C. Keenan, and Edith Kellman. Yerkes also served as an inspiration for other observatories, particularly Mount Wilson in California. An 1897 meeting at Yerkes to herald its opening is often been cited as a pivotal point in the formation of the American Astronomical Society. (I’ve been a member since 1992).

The centerpiece of the Yerkes Observatory has always been the 40-inch (102-cm) Alvan Clark & Sons lens housed in a Warner & Swasey-built mount. It was the largest refracting telescope in the world. Today, it remains a wonderful example of instrument-making art and craft. Over the years, the observatory acquired other instruments, including telescopes, spectrometers, micrometers, spectroheliograph, and specialized cameras and imagers.

A Change of Direction for Yerkes Observatory

There’s no question that Yerkes has an honored place in astronomy history. Yet, for all its storied background, the University of Chicago (its parent institution) didn’t want to keep running Yerkes anymore. The administration cited the very real costs of upkeep for the aging facilities as one reason. Also, encroaching light pollution has a serious effect on the institution’s ability to do advanced astrophysical observations. In 2005, the university announced it was going to sell the entire facility and grounds to a developer. The plan was to build luxury homes and other facilities. In short order, Yerkes would no longer be an observatory. This, despite its continued use as an educational facility.

The decision to turn Yerkes and its grounds into an exclusive homesite was not popular. In fact, the developer faced intense criticism, particularly among local residents. The astronomy education community was not happy about losing access to Yerkes. The outcry was effective and the development plans got dropped. That didn’t stop the university from looking for a way to unload the place. About a year ago (March 2018), they announced an October 1st closure of Yerkes to the public and continued to look for a way to dispose of the property.

The Yerkes Future Foundation Steps In

Not long after the closure decision was announced, a group of local residents called the Yerkes Future Foundation stepped up to the plate. They proposed to take over the facility and continue its mission and began discussions with the university. On November 6, 2019, the two sides announced an agreement in principle to transfer the property to the foundation. There are, as yet, no public details about the agreement itself.

There is some information available about future plans, however. The foundation will restore the buildings and telescopes and reopen the facility to the public. Educational programs for students, as well as access for astrophysicists, will be set up. These should preserve the Yerkes role in teaching the next generation of astronomers while promoting continuing research programs.

That’s where the future of Yerkes stands at the moment. I really do hope that this venerable place and its priceless Alvan Clark telescope will continue to be used. The mechanics are still good, and even though light pollution is brightening the nearby skies, there’s still science and learning to be done! Stay tuned as this saga continues forward.

Note: the book I referenced above is The Discovery of the Universe: A History of Astronomy and Observatories. It is due out next week in hardback in the UK and in electronic form in North America.