Wednesday, March 21, 2018

Instruments of Wonder: As one observatory prepares to make history, another seeks to preserve it.

About two weeks ago, in the coastal town of Redondo Beach, California, engineers at the headquarters of Northrop Grumman Aerospace Systems unpacked one heck of a box. Transported via the Space Telescope Transporter for Air Road and Sea, the contents were unwrapped with extreme caution by workers sporting cleanroom bunny suits. Inside were intricate pieces of the James Webb Space Telescope (JWST)—the space-bound observatory expected to revolutionize our understanding of the universe over the next decade.

An artist’s conception of the completed James Webb Space Telescope. The telescope will be launched into space on an Ariane 5 rocket next spring.
Image credit: Northrop Grumman (CC BY-NC-ND 2.0).
Two thousand miles away, in the small town of Williams Bay, Wisconsin, staff at the picturesque Yerkes Observatory were doing some unpacking of another sort—unpacking the news of an uncertain future. After more than 120 years of ownership, the University of Chicago had just announced plans to “wind down its activities” at the observatory and cease on-site operations this fall. The University’s Department of Astronomy and Astrophysics was housed at Yerkes until the 1960s, and has maintained the observatory for research and education activities through the decades.

If you follow astronomy, you probably know that southeastern Wisconsin is not a hotspot of observational activity. Its weather, elevation, and the lights of nearby cities obscures the faint signals of celestial objects. Places like the Atacama Desert in Chile and, well, space, are far better suited for observing. But things were different 120 years ago. When it opened in 1897, Yerkes Observatory boasted the largest telescope in the world, a 40-inch refracting telescope. It was that selling point—having a namesake that was the biggest of something—that convinced local opportunist Charles T. Yerkes to invest in the observatory. Two smaller, but world-class research telescopes joined the refractor in its new home.

The 40-inch refractor at Yerkes Observatory, 1897.
Image credit: Pubic domain.
Under the leadership of its founder, astronomer George Ellery Hale, Yerkes Observatory spurred the development of astrophysics as a field. Edwin Hubble and Carl Sagan did their thesis projects at the university, and astronomers like Subrahmanyan Chandrasekhar and William W. Morgan laid the foundation for our current understanding of the universe. Einstein spent a day at the observatory during his very first visit to the United States.

“Modern astronomy started here,” according to Dan Koehler, director of tours and special programs at Yerkes Observatory. Prior to Yerkes, he explains, astronomers were primarily concerned with charting stars and the orbits of planets and asteroids. Yerkes brought galaxies, nebulae, interstellar matter, and stellar evolution into focus. “[This work] started establishing our place in the universe, and certainly in the galaxy,” says Koehler.

Charles Yerkes might be pleased to know that his 40-inch remains the largest refracting telescope in existence—just don’t mention that it’s no longer the largest telescope. For practical reasons, a refracting telescope with 40-inch lenses is about as big as you can go. The Yerkes refractor is 63 feet long and requires a movable floor and a dome 90 feet in diameter. Research is now dominated by reflecting telescopes that use mirrors to focus light and are much more compact.

Yerkes Observatory.
Image credit: Charlie Vinz (CC BY-SA 2.0).
The Magellan telescopes and Giant Magellan Telescope in Chile now garner most of the attention of the University of Chicago’s Department of Astronomy and Astrophysics, and that’s understandable. The Magellan telescopes—there are two of them—have primary mirrors more than 20 feet in diameter. The Giant Magellan Telescope will be more than 80 feet in diameter, earning the title of largest optical observatory in the world when it begins collecting light.

Although its research life is over and the University of Chicago is moving on, the refracting telescope and its home are quite an attraction. Thousands of people are inspired by programs and stargazing events at the observatory each year. Yerkes hosts unique educational programs for students of different ages and abilities. The building is a great architectural study and, as many couples can attest, the grounds make a gorgeous backdrop for weddings. Fortunately, a dedicated team is exploring alternative management models to keep its doors open. As Koehler told worried Yerkes Observatory Facebook followers, “Rest assured that we're doing all we can to preserve our cherished Yerkes for current and future generations.”

In some ways, the contrast is stark. Giant Magellan and JWST are engineering marvels, cutting-edge research tools that will show us things no human has ever seen. Yerkes Observatory is an artifact of history that, while operational, is no longer pushing the limits of knowledge. The thing is, I’ve watched in awe as engineers assembled pieces of JWST. I’ve been left breathless by the view through the historic 40-inch refractor. I’ve stood on a rooftop on a clear night, unable to pull my naked eyes away from the encompassing Milky Way. In the 14-billion-year timeline of the universe, Yerkes, JWST, and modern eyesight aren’t really that different. All are contemporaries, inspiring wonder, curiosity, and exploration in humanity.

Kendra Redmond

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