April 11, 2008

In Today's One Minute Astronomer...

Yerkes Observatory

The world's largest refractor lives at Yerkes Observatory on Lake Geneva in Williams Bay, Wisconsin. More than a home for telescopes, Yerkes is the "birthplace of modern astrophysics" because it was the first observatory to house chemistry and physics laboratories to study astrophysical processes.

The Basics

• Yerkes Observatory was opened in 1897 as part of the newly-minted University of Chicago, a first-class university opened in 1892 and funded by John D. Rockefeller.

• George Ellery Hale conceived the idea of a giant refractor in 1892. Hale by chance overheard the famed lens-maker Alvin Clark declare that two optically perfect 40-inch glass disks were available for polishing into a lens. Hale himself was just hired at the University, and lived just a short distance away in Hyde Park in south Chicago.

• The telescope was financed by industrialist Charles T. Yerkes, whom Hale enticed with the promise of eternal fame as the namesake of the largest refracting telescope in the world.

• This first great age of astronomy, and of much of science, was financed by donations from the legendary businessmen of the day like Yerkes, Rockefeller, Andrew Carnegie, and James Lick.

Aerial photo of Yerkes Observatory

A Deeper Look

• Lake Geneva presented the best combination of clear, steady skies and proximity to the University. The site selection committee said, "The site is high and beautifully located, the atmosphere is clear, without danger from the encroachment of manufactories, railroads, or electric lights."

•The telescope tube and mount were displayed at the world expo in Chicago, although they were nearly destroyed during a fire in late 1893.

•Because a glass lens sags under the force of gravity and loses its carefully configured shape, no one has yet built a refractor with a lens larger than the 40" at Yerkes.

A Bit of History

The observatory was finally dedicated on Oct. 21, 1897, with a gala celebration that included university trustees as well visiting astronomers and physicists from around the world. The collection of astronomers at the dedication in 1897 formed the seed of what is now the American Astronomical Society.

Personal View

Palomar, Lick, and Yerkes... these are my favorite of the "classic" observatories. I've visited Lick and Yerkes this year... Palomar is not far behind. I make these sacrifices, dear reader, to present you with the wonders of these altars to astronomy.

Postscript

Much of the pristine forest surrounding Yerkes will be turned into a resort, though the observatory will remain a centre for astronomy education and outreach. As author Conrad Aiken said, "All things lovely will have an ending."

*** Highly Recommended ***