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.

Tours and Events

  • Saturday Tours
    Yerkes Observatory is open to the public every Saturday throughout the year. Hours and tour times vary a bit by season.

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

    Weekday Tour Schedule, April 2017 to May 2018:

    Apr 3 - May 24, 2017, 11 am and 2 pm, Monday through Friday.
    May 25 - Sep 1, 2017, 11 am, 12:30 pm and 2 pm, Monday through Friday.
    Sep 5 - Dec 29, 2017, 12:30 pm and 2 pm, Monday through Friday.
    Jan 2 - Mar 16, 2018, 2 pm, Monday through Friday.
    Mar 19 - May 23, 2018, 12:30 pm and 2:00 pm, Monday through Friday.

    The Yerkes Gift Shop is open weekdays 11 am to 3 pm.

    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 front (north) steps. Yerkes is a working scientific and educational facility. For the security of our staff and equipment the building's doors are always locked except during Saturday tour hours. The Observatory is open only for guided tours Monday through Friday at the times shown above. Self-guided tours of the building's interior are not allowed.

    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.

    Reservations are not required for individuals or for groups of 25 or less 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

  • Explore Scientific Weekend at Yerkes
    The staff of Explore Scientific, makers of high-quality telescopes, binoculars, eyepieces, microscopes and observing accessories will demonstrate and offer their products for sale at Yerkes Observatory May 26, 27 and 28, 2017. A full schedule of display hours will be posted here by May 15 and will include evening observing with their equipment, weather permitting, May 26 and 27 on the Yerkes property.

    For more information, click here

idata wcbvMaking Astronomy Accessible to the Blind – Students Partner with Professionals to Build New Software Tool

If intelligent life without sight exists on some distant planet in our galaxy, these lifeforms would still explore the universe; how?

This is a guiding question for Innovators Developing Accessible Tools for Astronomy (IDATA), a new research initiative supported by the U.S. National Science Foundation – STEM + Computing Partnerships (STEM+C) Program.

To learn more about this new program Yerkes Observatory is involved in click here

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.

For more information click here

Yerkes Obs