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.

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, 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, except during Saturday tour hours from 9:30 am to 1:30 pm. 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 accompaniment by a staff member are not allowed.

    PLEASE NOTE: The Observatory staff regrets that, due to its very unique architectural nature and historical significance, the building is not handicapped accessible. For more information about accessibility click the link below.

    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...

  • Star Parties: Public Observing Nights
    Held several times throughout the year, star parties are your chance to see amazing celestial objects through telescopes on the lawn, enjoy the constellations, and try out cool astronomy activities for the whole family.

    For more information, please click here

March 7, 2018: The University of Chicago has announced plans to wind down its activities at Yerkes Observatory in Williams Bay, Wis., over the next six months and to formally cease on-site operations by Oct. 1, 2018. Read the Press Release Here

The University and staff at Yerkes will honor existing commitments for events at the facility scheduled before Oct. 1, and will accept new bookings on a case-by-case basis.

The University is announcing the plans well in advance in order to engage with Yerkes staff and nearby communities, including the village of Williams Bay, in considering long-term plans for the Observatory.

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