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 Saturdays, Throughout the Year
Yerkes Observatory is open to the public from 9:45 a.m. to 1:30 p.m. every Saturday throughout the year, excluding Christmas and New Year’s Day. Our expert, engaging and entertaining tour guides provide a fascinating program covering the Observatory’s history, architectural detail, astronomical research, and a look inside the 90-foot dome at the 40-inch refractor, still the largest lens-type telescope in the world.

Our general public tours are most appropriate for ages 6 and up.

Saturday tours begin at 10:00 a.m., 11:00 a.m., and 12:00 p.m. Most tours last 45 to 50 minutes. We do not accept reservations. A suggested donation of $8 per person is requested to support our public programs. Groups of 20 or more should consider reserving a private program outside of Saturday public tour hours. For availability and pricing, call 262-245-5555, extension 825, or email tours@yerkes.uchicago.edu.

The interior of the 90-foot dome is not temperature controlled, so dress appropriately on the day of your visit the same as for any outdoor activity.

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.

On Saturdays before or after tours, 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 displays describe galaxies, nebulae, and the death of stars.

Yerkes also features a museum, developed and maintained by 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 profoundly affected not only the scientific community but also the residents and character of Williams Bay. The museum, open only during Saturday public tour hours, is located in the southeast transept of the main floor.

For more information about all Yerkes tour programs call 262-245-5555, extension 825, weekdays between 9:00 a.m. and 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 continuously.


Weekday Tours
Tours lasting about 50 minutes are offered weekdays describing the Observatory's history, the interior and exterior architectural detail and a look inside the 90-foot dome at the 40-inch refractor telescope.

Weekday Tour Schedule, August 2016 to May 2017:

Aug 1 - Oct 28, 2016: 10 am, 11 am and 2 pm
Oct 31, 2016 - May 24, 2017: 11am and 2pm

Labor Day: 10am, 11 am and 12Noon

The Yerkes Gift Shop is open 10:30 am to 3 pm weekdays.

Weekday visitors should plan to arrive no more than five to ten minutes before their selected tour time. A tour guide will meet visitors on the hour at the front (north) entrance, across from the parking are. The building's doors are always locked for security, except during Saturday tour hours. The Observatory is open only for guided tours Monday through Friday at the times shown above. The museum and displays are open on Saturdays only.

The cost is $10 per person age 18+, $8 per person age 6-17. Children under age 6 are admitted at no charge. Reservations are not required for groups of less than 20 people.

Our weekday tours are most appropriate for adults and children age 6 and older.

Private, one-hour tours for groups of 25 or more visitors can be scheduled Monday through Saturday at a mutually convenient time. Contact us for pricing and reservations at the telephone number or email address shown below.

The interior of the 90-foot dome is not temperature controlled. Visitors are encouraged to dress appropriately on the day of their visit as they would for outdoor activities.

Groups of 25 or more people are encouraged to make advance arrangements for tours by calling 262-245-5555, extension 825, weekdays between 9:00 a.m. and 4:00 p.m. Our office is not staffed outside of these hours or on weekends. Or, send email requests to tours@yerkes.uchicago.edu.The mailbox is monitored continuously.

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 different observing sessions with our 40-inch refractor or our 24-inch reflector telescopes, weather permitting, for participants who are age 10 and up.

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


Programs for Family, School, Scout, Church and other groups
Throughout the year Yerkes Observatory hosts general tours and programs during the day or evening for a wide range of organizations. Depending on the type of program desired, we can accommodate up to 100 people, Programs may include a tour of building, a look at the 40-inch refractor, limited observing with our telescopes and interactive educational programs and demonstrations. Please contact us at tours@yerkes.uchicago.edu, or 262-245-5555, ext 825, for pricing, date and time availability.


Corporate Events
Throughout the year Yerkes Observatory hosts special corporate events. Outside catering is permitted. Your program can include a tour of the building, and, weather permitting, observing with our large telescopes. Call 262-245-5555, extension 825 for more details and pricing.


Wedding Ceremonies
Yerkes Observatory can be a very unique and memorable location for your wedding ceremony. We are unable, though, to host wedding receptions.

For pricing and to begin planning your wedding at Yerkes, call 262-245-5555, extension 825, or email to dkoehler@yerkes.uchicago.edu.


Wedding, Engagement and Professional Photography at Yerkes
Outdoor wedding, engagement and other professional photography is permitted on the Yerkes Observatory property. We ask that all professional photographers contact us to prearrange a date and time, and to prevent conflicts with other events in and around the building. Photography sessions are not allowed before 2:00 pm on Saturdays.

The use of a drone aircraft on the Yerkes property without prior approval and supervision by a Yerkes staff member is strictly prohibited.

Consumption of alcohol is not permitted anywhere on Yerkes property. We request that all parties visiting Yerkes for the purpose of a photography session be respectful of the building, architecture, grounds and the educational environment of the facility.

We suggest an appropriate monetary donation of your choosing to help maintain our beautiful building, grounds and the continuing scientific and educational missions of the Observatory. Payment can be arranged using the contact information in the Wedding Ceremonies section above.


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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.)