Yerkes Observatory

Yerkes Observatory


Completed in 1897 and continuously owned by The University of Chicago’s Department of Astronomy and Astrophysics, Yerkes Observatory, known as the “birthplace of modern astrophysics,” offers daytime public tours Monday through Saturday throughout the year.  Our knowledgeable, experienced and entertaining tour guides conduct walking tours that last about 50 minutes 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, still the largest lens-type instrument in the world.  Check the website for current tour times and general information. The Observatory is closed on Sundays, Thanksgiving, Christmas and New Year’s Day. 

The interior of the 90-foot dome is not temperature controlled.  Visitors should dress appropriately on the day of their visit as they would for outdoor activities.
Yerkes is a working scientific and educational facility and the building is secured at all times.  Weekday visitors are greeted at the front (north) entrance five to 10 minutes prior to each tour time and are required to be accompanied by a tour guide throughout their stay at Yerkes.  Self-guided tours of the building’s main floor, displays and museum are only available on Saturdays from 9:45 am to 1:30 pm (10:45 am to 1:30 pm January 6 to April 28, 2018). All visits to the 90-foot dome housing the 40-inch refractor occur with an Observatory representative.

The cost for all daytime tours is $10 per person age 18+ and $8 per person age 6 to 17.  Children under age 6 are admitted at no charge.  Yerkes tours and displays are most appropriate for ages 6 and up.  Reservations are not necessary for groups of 25 or less people on weekdays or Saturdays.

Groups of 25 or more people are encouraged to make advance arrangements for a private tour at a mutually agreeable time Monday through Saturday by calling 262-245-5555, ext. 825, weekdays between 9:00 am and 4:00 pm.  Our office is not staffed outside of these hours or on weekends.  Email requests can be sent to [email protected]  The mailbox is monitored continuously.

Many viewing opportunities with the Yerkes 24-inch reflector and 40-inch refractor telescopes are offered every month of the year.  Public observing schedules are posted on the website.  Registration and payment of a fee are required to participate.
At the end of every weekday tour, and from 9:45 am to 1:30 pm on Saturdays (10:45 am to 1:30 pm January 6 to April 28, 2018), visitors are encouraged to browse our unique gift shop featuring postcards, apparel, photos from the Observatory’s archives, jewelry, meteorites, posters, books and many unique items found only at Yerkes Observatory. 


Known as the birthplace of modern astrophysics, Yerkes Observatory is open to the public for daytime tours Monday through Saturday and evening telescope observing programs, year round, excluding Thanksgiving, Christmas, and New Year’s Day.  Daytime tours provide a fascinating overview of 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. Evening observing tours are conducted with either the 40-inch refractor or the 24-inch reflector (mirror-type) telescopes. Check the website for a current schedule of daytime and evening program times.

Motorcoach/Group Tours

A must-see attraction for all motor coach excursions to Geneva Lake, Yerkes Observatory houses the "Great Refractor", the world’s largest lens-type telescope.  Group tours conducted by knowledgeable, entertaining and engaging guides can be arranged weekday mornings or afternoons and combine 19th century history and architecture with modern-day astronomy.  For information, pricing and to book a tour contact Dan Koehler, Director, Tours and Special Programs, 262-245-5555, ext. 825, [email protected]