The building is only open for guided tours provided by our staff.

The grounds around the Observatory are open from dawn to dusk, and a ticket is not required. Click here for more information about the grounds.

Please note that the grounds may very occasionally be closed for a private event. If this is the case, signage will be posted and we ask you please return another day.

Yes. The building is only open to the public for tours provided by our staff and for scheduled events. Visitors are not allowed to enter the Observatory unescorted. This is for the protection of the historic artifacts and equipment. This reflects the fact that the Observatory is still in active operation.

Purchase tickets here.

Yes.

Tickets to tour the building frequently sell out, particularly in summer, so we recommend reserving at least a few days in advance. We sell a limited number of tickets per tour; if a date does not show available tours, that means tickets are sold out or that is a day we have not yet posted tours for sale. Prices can be found by clicking the button below.

If there are tickets still available for a given tour, you may purchase them “on the spot” by checking with the staff member who will open the south (main) door of the Observatory starting 15 minutes before each tour start time. Please do not ring our doorbell prior to that time asking about available tour tickets– simply check online and purchase them there.

Please note that tour times are posted to the site on a rolling basis approximately 2-3 months ahead. If you are looking to book further ahead we may not yet have posted those tours for sale. Please check again a bit closer to your desired date.

Purchase tickets here.

Our tour schedule varies by season.

Summer
We offer public tours Thursdays through Mondays. The building is closed Tuesday and Wednesday.

Fall, Winter, Spring
Tour timing varies by week.

The easiest way to see if we are offering a tour on the day you plan to visit is to look at our calendar. If you do not see any clickable tours on the calendar, it means we do not have tours on that date, tickets for that date are sold out, or tickets are not yet available.

Purchase tickets here.

Unfortunately not. Admission tickets cannot be transferred, refunded or exchanged. All sales are final.

We can often offer help if you contact us at least one week in advance to let us know that you need to reschedule your tour. Please email us at info@yerkesobservatory.org and we will attempt to assist you in rescheduling your tour if possible. That said, if we cannot find a workable date for you, all sales remain final, and we do not offer refunds.

If you have missed your tour please do not show up for another date or time. We will, unfortunately, have to turn you away.

Ticket holders who arrive more than ten minutes late will not be admitted. We do not reschedule late arrivals or offer refunds.

We do not allow visitors without tickets to enter the building. If you have an unticketed guest with you and no space is available on your tour, they are welcome to walk the fifty acres of grounds while you are taking your tour. Please note that there are restrooms available in the Observatory building only for ticketed visitors.

Please check-in at the south doors of the Observatory. For reference, the main street is to the north. The lake is to the south. Check in at the door atop the south steps ten minutes before your tour start time. A Yerkes staff member will greet you and check you in.

Please note the entry is exposed to the weather, so plan accordingly. Even if it is pouring rain, we unfortunately are not staffed to allow you into the building earlier than 10 minutes prior to your tour.

You are more than welcome to arrive early to explore the grounds. Click here for more information.

Our tours are described below. If you are looking for accessibility information, click here.

SPACE & SPACES TOUR
This is our introductory Observatory tour. Your enthusiastic guide will provide a fast-paced, one-hour and fifteen minute overview touching on the history of Yerkes, the architecture and restoration, and highlight many of the famous astronomers who have worked here over the past 125 years.

You and up to forty other visitors will tour the main floor (rotunda, library, exhibits, and more), check out some historic astronomic glass plates, and conclude by visiting the dome housing the famous Great Refractor, the world’s largest refracting telescope. There is time for questions at the end. This tour involves navigating up and down one full flight of stairs.

Purchase tickets here.

HIDDEN SPACES TOUR
This in-depth tour, which is typically offered only once or twice a week for up to twenty visitors at a time, starts with many of the same highlights as our introductory tour but quickly spins off into an exploration of the fascinating people, unusual stories, hidden projects and quirky corners of the Observatory and its history. These tours are led by Yerkes Director Dennis Kois or one of our senior staff. Questions are welcome throughout.

In addition to the tour stops of our introductory tour you’ll visit one of the smaller domes which house our reflecting telescopes, view fascinating historic documents and tour the basement, attic, glass plate vault, dark rooms, labs and machine shops. This tour involves a lot of historic stairways, time on your feet, tight spaces, and even doing the limbo under some pipes in our attic. We do not recommend this tour if you have mobility challenges or cannot easily navigate stairs, including spiral stairs. The tour typically lasts an hour and forty-five minutes.

We are often asked if a visitor should take both tours. If you are deeply interested in the history of Yerkes and/or astronomy, we would say “yes.” There is some overlap between the tours, but less than you might think. That said, taking both the same day is a lot of time on your feet… plan accordingly!

Purchase tickets here.

ARBORETUM TOUR
This hiking tour lets visitors view the Observatory’s architecture and fifty acres of Olmsted-designed grounds (officially designated an arboretum in 2023) during an enjoyable 1.5 hour walking tour with a knowledgeable guide on trails, paths and through lawns and prairies.

This is an easy to moderately challenging 3-4 mile hike across a variety of open terrain and trails. The first hour takes you around the observatory grounds and through the restored prairies and pollinator meadows on level grass or crushed limestone trails. The final half hour of the tour navigates a mulched woodland trail with varying inclines including a steeper bluff at the end.

Arboretum tours take place rain or shine. Please dress for the weather, wear appropriate footwear and bring sunscreen and/or an umbrella. The tour may be canceled or shortened in the event there is lightning or extreme weather.

Purchase tickets here.

EXPLORING THE NIGHT SKY
From March through November Yerkes offers an evening tour that illuminates the inner-workings of Yerkes after dark.

These two hour tours are typically offered on select Friday and/or Saturday evenings, and include–weather permitting–the opportunity for telescope viewing with a knowledgeable astronomy guide using either the Great Refractor (our first choice) or the 24” reflector.

Tickets for these intimate tours of fifteen visitors are posted on our website and typically go on sale only a few weeks in advance. They sell out very quickly.

We cannot emphasize strongly enough that stargazing during your tour is 100% weather dependent. It is also reliant on the workings of a 125-year-old historic telescope that is more complicated and bigger than a city bus.

We work hard to ensure you will have a great experience whether the skies are clear or not, but we cannot guarantee the weather nor which telescope will be operational for your tour. We do not offer refunds or exchanges in the event that your tour is unable to look through a telescope or through the Great Refractor.

Purchase tickets here.

If you’d like to ensure you have the opportunity to look through a telescope at Yerkes on a clear night, please consider joining our Giving Circles.

In exchange for pledging to provide ongoing annual support of our mission, Giving Circle members receive special discounts and access each year, every year. At the Mary Calvert Society level and above, you will receive priority booking of night viewing programs and a 50% discount for up to two tickets! Plus a host of other discounts and special opportunities.

Learn more about Giving Circles

We cannot guarantee clear skies. In the event the weather does not permit observing or there are technical issues with the historic equipment, we guarantee an exclusive experience with your astronomy guide exploring the night sky from a historical perspective in some of the most peculiar spaces in Yerkes that the public are never allowed to enter.

We’ll delve into the secret vaults with 180,000 glass pictures of space, explore the evolution of astrophotography through over a century of equipment, and visit darkrooms in our subterranean chambers. This night trek will take you to the Great Refractor Dome, one of the two reflector telescope towers, and to the historic heliostat observatory in the attic.

You will receive an email by 2:00pm on the day of the tour to confirm the evening’s plan. Regardless of atmospheric conditions, this is a two-hour immersion inside the observatory that changed the way we see the universe.

We do not offer refunds or rescheduling if the weather does not permit observing or there are technical issues with the historic equipment. Regardless of atmospheric conditions, this is a two-hour immersion inside the observatory. The only instances where we will offer a reschedule or refund is if we have to cancel due to lightning or extreme weather.

This is a late night event, thus it’s an experience best enjoyed by ages 13 and up. Because of the historic construction of the building and the 125 year old domes, there are several flights of stairs (standard, steep, and tight spirals) that will be climbed and descended during both the clear and cloudy night programs. This experience is not wheelchair accessible.

Yerkes offers a very limited number of private telescope viewing events each year, which can be booked as part of a rental event at the Observatory. As with all viewings, private rentals are subject to the weather and thus we cannot guarantee conditions suitable for viewing on the night of your private event.

We also occasionally offer private observing rentals to well-established astronomy organizations and groups.

If interested, you may reach out to Walt Chadick at wchadick@yerkesobservatory.org.

Please check-in at the south (main) doors of the Observatory ten minutes before your tour start time. A Yerkes staff member will greet you and check you in.

Please note the entry is exposed to the weather, so plan accordingly. Even if it is pouring rain, we unfortunately are not staffed to allow you into the building earlier than 10 minutes prior to your tour.

You are more than welcome to arrive early to explore the grounds. Click here for more information.

Partly, but not entirely.

Yerkes has installed a handicap-accessible entrance as well as an accessibility lift to allow visitors with mobility challenges to bypass the entry stairs at our main entrance. This means that those visitors are able to tour the main floor of the building as part of our Space and Spaces Tour.

However, we do not yet have a means by which visitors on the Space and Spaces tours with mobility challenges are able to visit the main dome, which is at the top of a steep flight of steps and houses the Great Refractor. That is an accessibility challenge that we hope to overcome in the coming years.

Visitors on the tour who are unable to use the stairs up to the main dome may peruse several exhibits while the tour group is in the Dome.

If you decide to book tickets and will need to use the handicap entrance and lift, please let us know in advance so that we can properly prepare for your visit and assist you with parking, door entrance, and lift function.The handicap entrance and lift are not accessible without a staff escort.

Email us at info@yerkesobservatory.org at least 24 hours prior to your visit; we are very happy to help you!

The Observatory has fully ADA-compliant restrooms. There are also family
restrooms, along with changing tables.

Generally not, though there are paved driveways and sidewalks that allow viewing of both sides of the Observatory building.

There is also a half-mile ADA accessible trail loop that passes through a pollinator prairie and loops back via part of the original Olmsted ellipse (aka, driveway), which is not open to cars. Please be aware that we do have an apiary on site in case any of your guests have a bee-sting allergy.

The grounds around the Observatory are open from dawn to dusk, and a ticket is not required.

You are welcome to come and walk the four miles of trails on the property and view the architecturally marvelous observatory from outside. A tour ticket is required to enter the observatory. Our paved lot is reserved for guests who have tour tickets. There is a grass lot adjacent to the paved lot for arboretum visitors.

Please note that in winter our trails are not cleared and will be covered in snow and ice.

Yes. Pets are welcome but must be kept on a leash for the entirety of your visit. Visitors not keeping pets leashed will be asked to leave the grounds.

We also request that you clean up after your pet so our grounds can be enjoyed by everyone.

There are not. The only restrooms onsite are only available to those with tour tickets.

We recommend you make the two-minute drive to visit the Green Grocer, a nearby general store, coffee shop and deli to use their restroom and buy a snack. They have great food!

Guests who have reserved a ticket for a tour, observing night, private event, star party, or community event have the opportunity to visit the gift shop.

At this time the gift shop is not open unless you have a tour ticket or are visiting for an event or program. We do have a small but growing selection of items available online.

No. Yerkes is a cashless facility for tours, events, and the gift shop. We do accept cash donations which are immediately placed in a secure box reserved for donations.

There are not. The only restrooms onsite are only available to those with tour tickets.

We recommend you make the two-minute drive to visit the Green Grocer, a nearby general store, coffee shop and deli to use their restroom and buy a snack. They have great food!

Plausible, but unproven.

We’re a 125-year old observatory run by a mix of real-deal scientists and artsy types. The artists among us regularly hear ethereal moaning and see sparkling apparitions. The scientists among us keep proving those are the antique radiators and refracted light. We’ll let you know of any developments either way!

The non-profit Yerkes Future Foundation. You can learn more about the history of Yerkes here.

We’ve heard that one, too. Not true. The University donated the entire Observatory and the land to the Foundation as an act of community good. We thank them!

That’d be cool, but no. He did, however, film a 1996 movie called Chain Reaction at Yerkes.

We recently found a Laserdisc of it in the attic. We’re still looking for a Laserdisc player… but not too hard. It gets an 18% rating on Rotten Tomatoes.

Our community owes a debt of thanks to the early Yerkes Future Foundation trustees who signed on for who-knew-what before there were any staff or a plan. They worked for years to convince the University of Chicago to hand off the entire Observatory to a non-profit organization, and then helped recruit amazing early Trustees and bring on the founding staff to bring the project to life.

Founding YFF Board Chair: Dianna Colman

Early YFF Trustees: Frank Bonifacic, Bill Brownell, Sue Ann Callison, Robin Culbertson, Chuck Ebeling, Jeff Germanotta, Dana Hagenah, Mary Kilmer, Bob Klockars, Kate Lewis, Tom Nickols, Ted Parge, Peter Strothman, Aimee Tanking, Joe Madonia, Spencer Weber

Founding YFF Staff: Dr. Amanda Bauer, Will Borgen, Walt Chadick, Kate Chadick, Mallory Conlon, Erin Cullen, Ashley Killeen, Dylan Kleinschmidt, Dennis Kois, Phil Krueger, Jana Lund, Marc Stanek.

Founding YFF Volunteer Accountant, aka “THE BEST”: Peg Pollitt

Where’d you hear that? That’s classified.

Mostly true, though the plan came courtesy of the U.S. military. Come take a tour if you want to learn more about this truly, truly terrible idea (now declassified!).

We are pretty impressed by the dedication it took for you to find this entry at the bottom of our FAQs!

Yes. We invite select artists, scientists, and cultural producers to collaborate with us on projects that broadly explore astronomy, space, the history of science, big ideas, ecology, landscape and culture through the lens of other practices.

These collaborations have varied widely, from individuals invited to travel as our guests to research a possible project, to those visiting Yerkes exploring an idea for which we provide free housing… but they provide all else. In some cases these visits have developed naturally into full-on collaborations, funded commissions, research residencies, and partnership projects. Other times, not.

Since reopening Yerkes to the public in 2022, some of our collaborators have included Grammy-winning musicians Eighth Blackbird (returning in 2024), Brooklyn-based artist Ashley Zelinskie, former U.S. Poet Laureate Tracy K Smith, astronomer and public educator Dean Regas, and former Senior Scientist of the James Webb Space Telescope and Nobel Laureate Dr. John Mather.

At this time, we do not have a formal application or selection process. Please do your research about Yerkes and our recent efforts. If you think a visit to Wisconsin might be important for the work you wish to do, you should send a brief (again, brief) email of inquiry with relevant links to either Dennis Kois (Executive Director of YFF, for art or culturally-focused inquiries) or Dr. Amanda Bauer (Montgomery Foundation Deputy Director of YFF, for science-focused inquiries).

Yerkes is a small non-profit organization; thus, we have to pick and choose where we direct our efforts. Please know we appreciate your interest whether we are able to engage with you at this time or not!