We’re so excited to welcome you all for our 2026 Open House season! This year, there will be a couple of changes to this popular event. Our Open Houses will still include open exploration of the observatory, a scavenger hunt with prizes, engaging demos and hands-on activities, a chance to see the world’s largest refracting telescope up close, and so much more! The main change is related to parking: instead of trolleys transporting guests to and from Williams Bay School, guests will park on-site at the observatory. This also means fewer tickets will be available for each open house, though we are planning to host several more open houses throughout 2026.

Each event is rain or shine and includes a variety of activities for you and your family, with unique activities and themes. Make sure to save the dates below, or buy your tickets now! Remember, fewer tickets are available than previous years, so these events will likely sell out quickly.  

These events do not include the use of the telescopes in the building, though all will be welcome to see the Great Refractor dome and we will try to observe with smaller telescopes outside if clear. To ensure sufficient parking on-site, reservations are required. Tickets for this event cost $5 per child and $10 for adults and are available online only. Tickets for each event are available now on our ticketing website!

As we get closer to each event, please check back at our blog for a schedule of events. We hope to see you at one (or all) of our open houses this year!

• Friday, March 13, 2026, 8pm – 10pm: Messier Marathon with the Milwaukee Astronomical Society
• Saturday, April 25, 2026, 5pm – 7pm: Celebrating Arbor and Earth Day
• Thursday, May 21, 2026, 6pm – 8pm: Exploring Art @ Yerkes
• Saturday, June 20, 2026, 7pm – 9pm: Summer Solstice Celebration
• Saturday, July 31, 2026, 6pm – 8pm: The Wonders of Physics
• Saturday, October 17, 2026, 7pm – 9pm: International Observe the Moon Night

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