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Welcome to the
Detroit Observatory,

where Michigan’s History
is Written in the Stars

Plan to See the Stars

The Detroit Observatory has re-opened!  We welcome you to join us Friday evenings in April for exhibits, tours, presentations, and observing!

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Rediscover the Detroit Observatory

Take a virtual tour of this newly reimagined, one-of-a-kind place, where the spirit of science and discovery link the past and present.

Fitz 12" refractor endview and open dome slit
[about this photo]

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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[about this photo]

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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Upcoming Events

  • Jun. 2, 2022

    Thursday / 7:00 PM

    Movie Night@The Detroit Observatory: “A Trip to the Moon”

    Register
  • Jun. 10, 2022

    Friday / 8:30 PM

    Astronomy Night Open House

    Register

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

We have completed hiring our first cohort of docents, but we expect to have more openings in the future, so please check back!

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?

A docent is a person who acts as an educator and guide at a museum or, in this case, an historic observatory.  Their job is to help visitors have the best experience they can.

There are two kinds of docents at the Detroit Observatory: Astronomy Docents, who help with telescope operation and astronomy presentations, and U-M History docents, who help with history tours, presentations, and exhibits. Our docents will receive extensive training relevant to their responsibilities.  Prior experience in operating telescopes, giving tours, or understanding U-M history is not necessary.

These are paid positions, and application is through the U-M Student Employment Website.

 

We have completed hiring our first cohort of docents, but we expect to have more openings in the future, so please check back!

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?

A docent is a person who acts as an educator and guide at a museum or, in this case, an historic observatory.  Their job is to help visitors have the best experience they can.

There are two kinds of docents at the Detroit Observatory: Astronomy Docents, who help with telescope operation and astronomy presentations, and U-M History docents, who help with history tours, presentations, and exhibits. Our docents will receive extensive training relevant to their responsibilities.  Prior experience in operating telescopes, giving tours, or understanding U-M history is not necessary.

These are paid positions, and application is through the U-M Student Employment Website.

 

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.

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