Yerkes LionYerkes Lion YERKES OBSERVATORY
The University of Chicago

373 W. Geneva St, Williams Bay WI 53191 (Latitude 42 34.2, Longitude -88 33.4)

Visiting Yerkes Observatory: General Information

Tour Yerkes on Saturday Mornings All Year
Yerkes Observatory, completed in 1897 and owned by the University of Chicago, is open to the public from 9:45 am to 1:30 pm every Saturday throughout the year. Guided group tours begin at 10:15 a.m., 11:15 a.m., and 12:15 p.m. and last about 45 to 50 minutes. Reservations are not accepted. While there is no charge, we appreciate a suggested donation of $8 per person to support our tour programs. Groups of 15 or more should consider a private program outside of Saturday public tour hours. Call our tours phone number for availability and pricing.

Our expert, engaging and entertaining tour guides provide visitors with a fascinating program covering the Observatory's history and architecture, astronomical research, the Great Refractor telescope and the interior of the 90-foot dome -- one of the largest ever built -- as well as details about our amazing Universe. Guests will see the 40-inch refractor, still the largest lens-type telescope in the world, which began research work in 1897.

The interior of the 90-foot dome is not heated, so be sure to dress appropriately as if for the outdoor temperatures on the day of your visit.

Before or after each tour, visitors can view a timeline display on the main floor describing Yerkes Observatory's construction and early history and adorned with dozens of 1890s photographs from the Yerkes archives. Other interesting hall displays describe comets, galaxies, nebulae, and the death of stars.

Yerkes also features a Quester Museum, developed and maintained by the Explorare Questers, a group of talented volunteers with an interest in preserving local history. Artifacts and personal effects on display in the museum examine the lives of some of Yerkes Observatory's most famous astronomers, people who had profound effects not only on the scientific community but also the residents of Williams Bay. The museum is open only during Saturday public tour hours and is located in the southeast transept of the main floor.

Saturday visitors are encouraged to browse our unique gift shop featuring postcards, apparel, photos from the Observatory's archives, jewelry, meteorites, posters, books, aids for viewing the night sky and some unique items found only at Yerkes Observatory.

Our Saturday public tours are designed for families and small groups (less than 15 people). Information about larger group tours or other customized, private programs can be found below.

For more information about all Yerkes tour programs call 262-245-5555, ext. 880, weekdays from 9:00 a.m. to 4:00 p.m. Our office is not staffed outside of these hours or on weekends. Tour questions can also be emailed to tours@yerkes.uchicago.edu. The mailbox is monitored seven days a week.


Weekday Tours
Tours lasting 45 minutes describing the Observatory's history, rotunda and exterior architecture, and the 40-inch refractor telescope are offered most weekday mornings at 9:00, 10:00 and 11:00 am, and most weekday afternoons at 1:00, 2:00 and 3:00 pm. Reservations are not required. The cost is $8 per person for ages 10 and older.

Weekday group tours for more than 12 people should be scheduled in advance. Please call our Tours phone number, 262-245-5555, ext. 880, or contact us at tours@yerkes.uchicago.edu for date and time availability, and pricing.

Weekday visitors should plan to arrive close to their selected or pre-scheduled tour time and will be greeted at the door by a tour guide, on the hour.

Private, one-hour tours at a cost of $100 per hour for one to 50 people can be scheduled after 4:00 pm weekdays, after 2:00 pm Saturdays or from 10:00 am to 4:00 pm Sundays.

The interior of the 40-inch refractor telescope dome is not heated, so be sure to dress appropriately as if for the outdoor temperatures on the day of your visit.

At the end of the tour visitors are encouraged to browse our unique gift shop featuring postcards, apparel, photos from the Observatory's archives, jewelry, meteorites, posters, books and some unique items found only at Yerkes Observatory.


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Observe through a Yerkes Observatory Telescope!
From season to season the evening sky changes slowly and reveals many different celestial wonders visible with, and without, optical aid. Every month during the year, on select weekday and weekend evenings, Yerkes Observatory offers observing sessions with our 24-inch diameter reflecting telescope, weather permitting, for participants who are age 10 and up.

For available observing sessions and reservation info click here...


Programs for Families, Schools, Scouts, etc.
Throughout the year Yerkes Observatory hosts general tours during the day or in the evening. We can accommodate up to fifty, depending on the program. The charge per group for a one-hour program is $100.00. To reserve a mutually agreeable date and time, please contact Richard Dreiser at 262 245-5555, ext 880, or, send email to: rdd@yerkes.uchicago.edu


Corporate Events
Throughout the year Yerkes Observatory can host special corporate events. You may make arrangements for outside catering. These programs can include tours, and, weather permitting, observing through telescopes. Call 262 245-5555, extension 810 for a price schedule and other details.


Wedding Ceremonies
Yerkes Observatory can be the site for your Wedding Ceremony. We do not hold Wedding Receptions though. For a details, contact Richard Dreiser at 262 245-5555, ext 880, or send email to: rdd@yerkes.uchicago.edu


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Map to Yerkes Observatory


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Directions to Yerkes Observatory

From Chicago:
Take Highway 94 North to Highway 50. Turn left, and go west on highway 50 into the city of Lake Geneva. Proceed about six miles to the intersection of Highway 67. You will see Mercy Clinic on your left. Turn left onto Highway 67 and continue downhill almost exactly one mile (you will pass the "Lighthouse" Restaurant on your right) to where Highway 67 does a t-intersection with Geneva Street (the Williams Bay Fire Department is immediately ahead of you). Turn right, and go uphill, curving to your left on Highway 67/Geneva Street almost exactly one mile up to the unlit brown sign with white lettering that says YERKES OBSERVATORY. (Please note that, because of ongoing research, our sign is NOT lit up.) Turn into the Yerkes Observatory Drive, and park in front of the Observatory. (If you see the illuminated Aurora University sign on your left, you've gone exactly one block too far. Turn around.)

From Milwaukee or Beloit:
Take Highway 43 all the way to the Highway 67 Elkhorn/Williams Bay exit. Turn south onto Highway 67 towards Williams Bay, and drive about six miles to the intersection of Highway 50. Cross Highway 50 (you will see Mercy Clinic immediately on your left) Continue downhill almost exactly one mile (you will pass the “Lighthouse” Restaurant on your right) to where Highway 67 does a t-intersection with Geneva Street (the Williams Bay Fire Department is immediately ahead of you). Turn right, and go uphill, curving to your left on Highway 67/Geneva Street almost exactly one mile up to the unlit brown sign with white lettering that says YERKES OBSERVATORY. (Please note that, because of ongoing research, our sign is NOT lit up.) Turn into the Yerkes Observatory Drive, and park in front of the Observatory. (If you see the illuminated Aurora University sign on your left, you've gone exactly one block too far. Turn around.)