Science & Research

Look through a historic telescope. Walk the grounds. Hear new ideas take shape. Science at Yerkes connects what we see in the sky with how we think, question, and discover.

Science, All Around You

Science at Yerkes shows up in more than one place, from the telescope above to the world around you.

40-Inch Historic Refractor

Explore the world’s largest refracting telescope.

Explore the Refractor

24-Inch Reflecting Telescope

See a research grade f/13.5 Cassegrain Boller & Chivens telescope completed in 1967.

See the Telescope

41-Inch Reflecting Telescope

Discover a research grade f/8 Ritchey Crétien telescope completed in 1967.

See the Telescope

Glass Plate Collection

Browse our collection of photographic glass plates taken between 1889 and 2002, which house 180,000 individual astronomical images and spectra.

Browse the Collection

Instrumentation Labs

Visit the labs that support instrumentation development and innovation, telescope maintenance, and custom 3D printing.

Visit the Labs

Historic Collections

Explore the Yerkes libraries, which contain astronomical and personal journals and books from former observatory staff.

Historic Collections

Tours & Events

Step Into Science

There’s is no single way to experience science at Yerkes. You can observe, listen, participate, or simply take it in.

Space & Spaces Tour

Stand beneath the world’s largest refracting telescope. Explore sweeping architecture and the human stories that shaped modern astronomy.

Director’s Hidden Spaces

Wind through staircases, corridors, and tucked-away rooms rarely open to the public. A behind-the-scenes look at the observatory few get to see.

Open Houses

Hands-on discovery for all ages. Interactive demonstrations, themed evenings, and joyful exploration across science, art, and nature.

Exploring the Night Sky

An intimate evening beneath the dome. When skies are clear, view the cosmos through the Great Refractor and experience astronomy as it was meant to be.

SOLD OUT – Exploring the Night Sky with the 24″ Reflector

This tour is sold out for 2026. This immersive 2-hour experience illuminates the inner-workings of Yerkes after dark.

SOLD OUT – Open Houses

Our Open Houses are sold out for 2026. Check back for more info in 2027! Hands-on discovery for all ages. Interactive demonstrations, themed evenings, and joyful exploration across science, nature, history, and the arts.

SOLD OUT – Exploring the Night Sky

This tour is sold out for 2026. When skies are clear, view the cosmos through the Great Refractor and experience astronomy as it was meant to be.

Astronomy on Tap

Join us at Duesterbeck's Brewing Company (N5543 County Rd O, Elkhorn, WI) on Friday, October 9 at 6 p.m. for this free event.

For Researchers

Continue the Work of Discovery

The questions that shaped Yerkes are still being asked today. Researchers come here to explore new ideas, build on past breakthroughs, and work in a setting that invites focus, curiosity, and collaboration.

For Students

Summer Research Internships

Each summer, undergraduate students work alongside researchers at Yerkes, gaining hands-on experience with telescopes, astronomical data, historic archives, and science communication while contributing to real research projects.