The University of Chicago

373 W. Geneva St, Williams Bay WI 53191 (Latitude 42 34.2, Longitude -88 33.4)
Look Through a Large Telescope at the Moon, Planets, Galaxies, the Milky Way, Nebulae, Star Clusters and More at Yerkes Observatory!

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 observing sessions with our 24-inch diameter reflecting telescope, weather permitting, for participants who are age 10 and up.

We are now accepting reservations for these October 2015 dates:

October 1st, 2nd, 3rd, 4th, 7th, 8th, 10th, 11th, 12th, 13th, 14th, 18th, 20th, 21st and 31st.

Programs begin promptly at 7:00 pm. Plan to arrive between 6:45 and 7:00 pm. The building opens at 6:45 pm..

On these October dates, a second “late program” will begin at 9:30 pm. Plan to arrive between 9:15 and 9:30 pm. The building opens at 9:15 pm.

October 2nd, 3rd, 10th, 11th, and 31st

Please mention "late program" in your reservation request if you wish to attend one of these sessions.

Any October date not shown above is either sold out or is not available for public observing.

Public observing events at Yerkes are very popular and sell out quickly. Space on each tour is limited and subject to availability. Sessions last approximately 90 minutes to two hours. Scheduled sessions can be canceled due to adverse weather conditions (clouds, rain, high winds) and, in rare circumstances, Observatory event conflicts that arise after public observing dates have been announced.

The cost to participate is $35 per person, payable the evening of the event by cash, VISA or Mastercard. Reservations are required and can be made by email only at Please use this email address for reservations and questions concerning the 24-inch telescope program only.

For information and questions about the Observatory’s other tours please email (monitored seven days a week) or call us at 262-245-5555, 9:00 am to 4:00 pm, weekdays. The Observatory office is not staffed outside of these hours, or on weekends.

When requesting reservations for the 24-inch telescope program, include the name of the group organizer, an email address they can access the day of the event, their cell phone number and the number of people in the party. Groups of four or more will be asked for a non-refundable 50% deposit three days before the event. Deposits are refunded only if sessions are canceled due to weather conditions, equipment failures or Observatory facility conflicts. Reservation requests will be answered by an Observatory representative with additional information and instructions pertinent to your visit.

Scheduled event dates are removed from the above listings as quickly as possible after each sells out.

Public observing dates for November 2015 will be posted here about October 25th.

IMPORTANT NOTE: Participants **must be physically fit** and able to climb 40 steep, winding stairs from the ground floor of the building to the observing dome of the 24-inch reflector. Standing for about one hour or more on the telescope's elevating floor is required. Sensible shoes must be worn. Note that we do not allow high heels, flip flops, or open-toed sandals for safety reasons.

During autumn evenings from the dark sky environment at Yerkes you may see superb views of the moon, some planets, constellations, hundreds of stars, star clusters, nebulae, galaxies, the Milky Way, an occasional meteor and artificial satellites. Binoculars can enhance your viewing experience, but are not necessary.

For information about regularly scheduled Saturday tours, weekday tours, and other events, please click here.