The University of Chicago

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

The birthplace of modern astrophysics
Yerkes Observatory is a facility of the Department of Astronomy and Astrophysics of the University of Chicago. It was established in 1897 on Geneva Lake in Williams Bay, Wisconsin. Until the mid-1960's, Yerkes Observatory housed all of the Department's activities. Today the 77-acre, park-like site in southeast Wisconsin provides laboratory space and access to telescopes for research and instruction.
Yerkes Observatory occupies a unique niche for the educational and the scientific community. It bridges several important perspectives in formal and informal education. The history of astronomy and astrophysics of the observatory is a solid foundation for introducing all the important topics in current research as well as the practice of observational astronomy. There is a huge range of opportunities for learning. Because of Yerkes' historical context, the world of professional and student astronomers and astronomy educators is drawn to the observatory. These communities learn from one another, build relationships, and create programs, which result in enriched experiences and learning opportunities for young and diverse members of our society.

Yerkes Observatory is open for public tours  every Saturday throughout the year. We also offer group tours and special programs.

Upcoming Events

  • Regular Saturday Tours
    Yerkes Observatory is open to the public from 9:45 am to 1:30pm every Saturday throughout the year. Guided tours begin at 10:00 am, 11:00 am and Noon.

    For more information, click here
  • Weekday Tours
    Visitors may tour Yerkes Observatory most weekday mornings or afternoons.

    Weekday Tour Schedule, Summer 2016:

    May 18 - 25, 11:00 am and 2:00 pm
    May 26 - 27, 10:00 am, 11:00 am and 2:00 pm
    Memorial Day - May 30, 10:00 am, 11:00 am and Noon
    May 31 - Jul 1, 10:00 am, 11:00 am and 2:00 pm
    Jul 4 - 29, 10:00 am, 11:00 am and Noon
    Aug 1 - Sep 2, 10:00 am, 11:00 am and 2:00 pm

    Weekday visitors should plan to arrive no more than five to ten minutes before their selected tour time. The Observatory is open only for guided tours Monday through Friday at the times shown above. The cost is $10 per person age 18+, $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. Reservations are not required for individuals or groups of less than 20 people.

    For types of tours, pricing and more info click here
  • Observe through a Big Telescope
    Throughout the year, weather permitting, Yerkes Observatory offers evening observing sessions for visitors age 10 and up. Participants have a unique opportunity to view at a variety of fascinating celestial objects through either 40-inch refractor or 24-inch reflector telescopes...

    For more inormation, more...

    Give the gift of astronomy to your friends and family! Gift certificates valid for 15 months may be purchased for the Yerkes 40-inch and 24-inch telescope viewing programs. Please call 262-245-5555 ext. 825 for more information and to purchase a gift certificate, or email

  • Yerkes Observatory Summer Camps
    Yerkes Observatory is once again offering Yerkes Summer Camps for grades 3-8 and Tech Camps for grades 6-8, including an all-girls only version... click here

The education programs are made possible in part through SOFIA Outreach at Yerkes Observatory.

University of Chicago Press release: Middle schoolers to explore sky with robotic telescopes

Yerkes Study Group (YSG)
The Yerkes Study Group was formed to explore the best use of Yerkes Observatory as a future site for a regional center for science education. To download the final report (pdf file) of the YSG click here
Yerkes Obs