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
Yerkes Observatory is open to the public 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.

ACCESSIBILITY INFORMATION: The Observatory staff regrets that, due to its very unique architectural nature and historical significance, the building is not handicapped accessible. Some standing, walking and stair climbing is necessary to participate. A comfortable waiting area is available for visitors who cannot participate in all or part of our tours. Assistance and special accommodations for visitors are provided upon request when possible. The Observatory does not offer wheelchairs for use in the building.

Saturday Tours Schedule June through September 2018:
Jun 16 to Sep 29, 2018, the building opens at 9:45am and closes at 1:30pm. Tours begin at 10am, 11am and 12Noon.

We do not accept reservations and we always have plenty of space for visitors. The Tours staff encourages visitors to choose the tour time that works best for them and arrive about 10 to 15 minutes before the start of their selected program.

The cost is $10 per person for adults and $8 per person for ages 6 - 17. Groups of 25 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.

At the end of the tour visitors are encouraged to browse our new and expanded gift shop featuring postcards, apparel, photos from the Observatory's archives, jewelry, meteorites, rocks, books, children's items and many unusual, beautiful and truly unique items found only at Yerkes Observatory. The gift shop is open 9:45am to 1:30pm on Saturdays.

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..


Tour Yerkes Monday through Friday every week.
Tours lasting about one hour 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. Participating in a scheduled tour is the only option for visitors to see the interior of the building, and the 40-inch refractor, Monday through Friday.

Weekday Tour Schedule, June through September 2018:
Jun 11 - Aug 31, 2018, 11am, 12:30pm and 2pm, Monday through Friday.
Sep 4 - Sep 28, 2018, 12:30pm and 2pm, Monday through Friday.

Independence Day, Jul 4, 2018, 11 am ONLY
Labor Day, Sep 3, 2018, 11 am ONLY

The Yerkes Gift Shop is open weekdays during tours, and Saturdays 9:45am to 1:30pm.

Admission to the building for weekday tours begins 15 minutes before the scheduled start of each tour. A tour guide will meet visitors on the front (north) steps. Yerkes is a working scientific and educational facility. For the security of our staff, our students and our equipment the building's doors are always locked on weekdays. The Observatory is open only for guided tours Monday through Friday at the times shown above. Self-guided tours or access to any parts of the building's interior without the accompaniment of a staff member are not allowed.

ACCESSIBILITY INFORMATION: The Observatory staff regrets that, due to its very unique architectural nature and historical significance, the building is not handicapped accessible. Some standing, walking and stair climbing is necessary to participate. A comfortable waiting area is available for visitors who cannot participate in all or part of our tours. Assistance and special accommodations for visitors are provided upon request when possible. The Observatory does not offer wheelchairs for use in the building.

The weekday tour cost is $10 per person age 18 and over, and $8 per person age 6-17. Children under age 6 are admitted at no charge. Daytime tours are most appropriate for ages 6 and up.

We do not accept reservations and we always have plenty of space for visitors. The Tours staff encourages visitors to choose the tour time that works best for them and arrive about 10 to 15 minutes before the start of their selected program.

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 new and expanded gift shop featuring postcards, apparel, photos from the Observatory's archives, jewelry, meteorites, rocks, books, children's items and many unusual, beautiful and truly 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...


Wedding, Engagement and Professional Photography at Yerkes
Outdoor wedding, engagement, graduation, family and all other professional photography at Yerkes is permitted -- HOWEVER all professional photographers MUST contact us to prearrange a date and time to prevent conflicts with other events in and around the building.

Professional photography inside the building is NOT permitted at any time.

Outdoor photography sessions ARE NOT ALLOWED before 2:00 pm on Saturdays or before 5:00 pm weekdays. PAYMENT OF A FEE IS REQUIRED for all professional photography sessions.

To schedule and make a payment by credit card for a professional photography session please call 262-245-5555, ext. 825, between 9 am and 5 pm weekdays. Checks and cash are not accepted.

THE USE OF DRONE AIRCRAFT ON THE YERKES PROPOERTY IS STRICTLY PROHIBITED.

Consumption of alcohol and smoking are not permitted anywhere on the 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.


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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.)