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Please Pardon Our (Star) Dust

The Detroit Observatory is currently closed while undergoing a renovation and expansion that will add 7,000 square feet of new space for classes, events, and exhibits. A grand reopening is anticipated for spring 2022. Check back here for more details as this project progresses!

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Welcome to the
Detroit Observatory,

where Michigan’s History
is Written in the Stars

Plan your Visit

We expect the Detroit Observatory to re-open fully in spring 2022. Please check back for more information as that time approaches. In the meantime, watch the Observatory construction in real time!

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Fitz 12" refractor endview and open dome slit
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The 12" Fitz refractor in the dome. Photo by Shannon Murphy.

Fitz Refracting Telescope

When it was installed in 1857, the Fitz telescope was the third-largest refracting telescope in the world. More than 20 asteroids and 3 comets were discovered by astronomers looking through its lens. Today, visitors can still see the stars through this working instrument.

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The 6-inch Henry Walker Meridian Circle telescope, located in the east wing. In the foreground is the observer's bench.

Meridian Circle Telescope

Built in 1854, this telescope’s purpose was measuring with extreme precision the position of stars and other celestial bodies. It was designed for research and as a time-setting tool for business and railroad stations throughout the state. It was the most cutting-edge technology for its time.

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Are You Interested in Helping Detroit Observatory Visitors Explore the Sky?

Would you like a job helping visitors explore the sky using Detroit Observatory telescopes? Giving history tours of the Detroit Observatory or of the University of Michigan campus? Helping educate visitors using Observatory exhibits and facilities? Helping develop and mount exhibits on astronomy, other sciences, the history of U-M, and more? Then consider working with the Observatory.

Would you like to give history tours of the Detroit Observatory or of the University of Michigan campus? Help educate visitors using Observatory exhibits and facilities? Develop and mount exhibits on astronomy, other sciences, the history of U-M, and more?

When the Observatory re-opens, we expect to hire paid Student Docents, positions that will be open to qualified U-M undergraduate students. While prior experience with astronomy, telescopes, or University history will be welcome, it will not be necessary.

We will post positions when we are able, so check back here for more information, including pay rates, minimum qualifications and requirements, and the application process.

At a Glance

Quick facts about the Detroit Observatory

2019 cistern discovery

In 2019, construction crews excavating for the Observatory’s addition discovered a forgotten cistern on the south side of the building. The cistern — 10 feet in diameter and 12 feet deep — contained 4000 gallons of water that had to be pumped out and trucked off site. The construction date of the cistern and what was connected to it remain unknown.

Central telescope pier

The Observatory’s larger of two telescopes stands on a central pier, designed to minimize vibrations. The pier, constructed of solid brick masonry, is submerged 15 feet below grade, rises to the dome 40 feet above ground level, and is 20 feet in diameter at its base. It is isolated from the ground and dome floors by a 1-inch gap.

Dome rotation

The Observatory dome originally ran on five cannonballs that rolled freely in a circular groove. Because nothing maintained the distance between the cannonballs, they would eventually clump together toward one side, making rotation impossible. When this happened, timbers were inserted into slots in the dome, the dome was “jacked up,” and the cannonballs redistributed. In 1890, the system was replaced with railroad-style wheels running on a track, as can be seen today.

Watson’s discovery of Juewa

On October 10, 1874, James Craig Watson, while on expedition in China, discovered an asteroid — his 16th. Although asteroids were traditionally named for figures from Ancient Greek mythology, Watson asked his Chinese hosts to provide the name. They chose “Juewa” (瑞華星 ), or, “Star of China’s Fortune.” 139 Juewa was the first asteroid discovered in China.

Fitz lens cell

The Fitz refractor’s objective lens (the lens at the large end of the telescope) is known as a doublet achromatic lens. It consists of two lenses, one concave and one convex. This combination of lenses helps to reduce the image distortions caused by the fact that light of different colors come into focus at different points; the concave lens corrects for these distortions made by the convex lens.

Student transit I

In 1878, a small observatory was constructed 100 feet southeast of the Detroit Observatory, in anticipation of observing the transit of Mercury across the Sun, which occurred on May 8 of that year. This observatory was responsive to a program of the federal government to observe the transit and was temporarily made a U.S. Government Station.

Schaeberle comet discovery

On July 14, 1881, Observatory astronomer J. Martin Schaeberle discovered his second comet. A student described it thus: “With another woman student I had been working under Mr. Schaeberle’s supervision … until the wee hours of the night … Presently, [Schaeberele] hurried into the observatory and asked to use the telescope. We found that he had seen a comet …”

Director’s Residence

In 1868, a residence for the director and his family was built to the east of the Observatory. The residence was enlarged and updated in 1905. Beginning with James Craig Watson, seven directors and their families lived in the residence. In 1942, it became a residence for women students, in 1946, it was converted to apartments for faculty, and in 1954 it was torn down to make room for the expansion of Couzens Hall.