Saturday, October 4, 2008

Yerkes Observatory Tour

Last weekend while we were visiting friends Dave and Joan Oesper in Dodgeville, Wisconsin, they invited us to join them today on a tour of Yerkes Observatory they had organized. Built by the University of Chicago over 110 years ago, it is on the northwestern shore of Lake Geneva in the town of Williams Bay, Wisconsin. Of course, 110 years ago, it was a pretty rural area, and the 85 mile distance from Chicago was quite the buffer from the lights, smoke and other detriments of the big city.

Of course, times have changed, the population has grown and the truly great sites for astronomy have moved to the mountainous southwest, the volcanic peaks of Hawaii, or the desert peaks of Chile. But the past still echoes through the halls of the Observatory, and it was really cool to get a chance to see some of the great instruments of the 19th century.

The day was just spectacular with perfectly blue skies, highs in the 60s, and the beginnings of fall foliage visible throughout the trip. Fortunately our friend Carolyn was able to join us for the day. We met the crew from Dodgeville at a local restaurant for lunch - Daddy Maxwell's Arctic Circle Cafe (really - it was great!). Our tour was lead by staffer Richard Dreiser who has been doing public access for the Observatory since 1981. We started out touring the exterior architecture of the main building. There are fantastic figures of not only zodiacal constellations, moon phases and ancient gods, but griffins and possible caricatures of university presidents and financial benefactors.

After a walk around the building we entered the great dome of the 40" telescope. While most observatory tours tell you that a: the 40" refers to the diameter of the telescope and b: no one uses lenses anymore, only mirrors, THIS place DOES use lenses and, in fact, the 40" lens used here is largest refracting telescope in the world. Once inside, you can see one of the basic disadvantages of big refractors (telescopes that use a lens). To work well, the telescopes need to be long to minimize color errors, and these long telescopes need BIG domes to shelter them from the elements. And of course, bigger structures mean bigger budgets to build them. After a couple of decades of working around the big reflector telescopes in Arizona, the huge dome seemed so vast and roomy - in fact, you could likely get a game of volleyball going, yet, the structure needed to be large to be able to access all parts of the sky with the long instrument. We all got to ride the floor up and down (though not all at one time because of weight restrictions), and saw the telescope move across the sky (with the clickity clack of relays), but unfortunately we did not get a chance to see the big lens (I did ask!).

We exited the dome on the upper floor and walked through part of the old library with interesting titles like "Journal of Quantitative Spectroscopy and Radiative Transfer", and through some of the old men's and women's dorm rooms before entering one of the other domes which held a "new" scope - a 50 year old 24" Boller and Chivens reflector that is currently used for the public observing sessions. I actually learned astronomy in the 70s with an identical telescope to this one at the University of Iowa... After another demonstration of telescope motions, we went down a dizzying spiral staircase and saw some of the old instrumentation and photos of the old days - like when "Professor Einstein" came by to visit in 1921. I love these historical displays, including a front page of a Chicago newspaper covering the dedication in 1897. Amazingly, the displays at the "new" Observatories, like Kitt Peak southwest of Tucson (celebrating it's 50th anniversary this year) has boring displays in comparison, showing nothing of it's history or instrumentation, just a few pretty pictures and some scientific principles. Its the cool hardware, no matter how old, that is interesting to me!

There is a bit of a visitor souvenir shop where you can get a t-shirt or postcards. Interestingly, they sell meteorites, at what seemed like reasonable prices - $40 for a golf ball sized iron (which weighs a LOT more than a golf ball!). I bought a book on Yerkes' history, and Melinda got us some t-shirts. We socialized a bit more at a local ice cream stand, and finally headed home to St Charles, arriving just about sunset on a perfectly glorious day(about a 90 minute drive from Williams Bay).

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