[3] Immediately afterward, Tappan was approached by Detroit businessman (and former Michigan Attorney General) Henry N. Walker, who offered assistance.

This included $4000 of Walker's own money, and contributions from Lewis Cass, Henry Porter Baldwin, Senator Zachariah Chandler and others.

Additional funds were supplied by the Board of Regents of the University of Michigan, giving a total of $22,000 for the building and instruments.

[10] In 2019, the building closed for construction of the Classroom and Accessibility Addition intended to support expanded programming, reopening in April 2022.

[11] The faculty of the Detroit Observatory made significant contributions to the development of American astronomy in the second half of the 19th century.

[5][6] Brünnow was an astronomer at the Royal Observatory in Berlin, then under the direction of Johann Franz Encke, when Tappan met him.

Brünnow agreed to oversee on Tappan's behalf the fabrication of the meridian circle telescope by the German firm Pistor & Martins.

[6] The legacy of the program that Brünnow launched was that by the end of the century, by one estimate, about a quarter of the leading astronomers and meteorologists in the United States had trained at the Detroit Observatory.

[14] Watson continued the rigorous program of education and research that Brünnow had started — although he was by many reports an indifferent instructor, except with those in whom he saw significant talent for astronomy.

Among Watson's most significant accomplishments was the discovery of six asteroids in one year, 1868, an unprecedented achievement for which he was awarded the Lalande Prize by the French Academic of Sciences.

[15] Among Brünnow's students during his tenure at the Detroit Observatory were Asaph Hall, De Volson Wood, Cleveland Abbe, and James Craig Watson.

Watson served for 16 years, and among his students were Otto Julius Klotz, Robert Simpson Woodward, George Cary Comstock, Marcus Baker, and John Martin Schaeberle.

[5] The structure is constructed of solid brick clad with stucco originally painted to resemble granite blocks.