The Detroit Observatory and its Legacy for University of Michigan Astronomy

Editor's Note: Andrew Fraser grew up in Muskegon and was a member of GRAAA in the 1960’s while a student at Grand Valley State University. After graduate work at the University of Michigan, he went on to a long business career in the Minneapolis area, where he also continued his avocational interest in astronomy as a founding member of the Minnesota Astronomical Society, Inc. As retirement approached, he decided to obtain a masters degree in astronomy. He presently consults and tutors in astronomy, and later this year he will be assuming a teaching position at the University of Minnesota. This article is based on an essay he wrote as part of his graduate course requirements.

Figure 1: Detroit Observatory, 1858.

Photo credit: Bentley Historical Library


The Detroit Observatory is a historic astronomical facility located on the Ann Arbor campus of the University of Michigan. The original structure and its early instruments were a foundational facility for the University of Michigan, Department of Astronomy, which developed into an important center for astronomical research. The facility is significant for its pioneering presence, educational practices, discoveries, and the educators, students and researchers of note who have been affiliated with it.

Today the Detroit Observatory is no longer a research facility, but it has been painstakingly restored as a site of historical significance to both the University of Michigan and the astronomical community. Its physical presence is testimony to the first research facility of the university and the vision of that institution’s first president to establish it as a center of scientific learning and investigation. The legacy of the Detroit Observatory is a rich scientific history and institutional reputation for development of astronomical observation facilities and continued significant astronomical research to the present (Kinney 2008).

Foundation and Early Work

In the early 1850’s the state of Michigan was very much still on the American frontier. Michigan had become a new state in 1837. That same year, the University of Michigan, founded thirty years earlier in Detroit, moved to Ann Arbor, a town which had been in existence only thirteen years and had a thriving population of 2000(UMweb). The school operated with out a president for more than a decade with the faculty annually electing one of its own to preside as leader. In 1852 the school’s first President, Henry C Tappan, was appointed. It was Tappan’s vision to complement the classical course of instruction with the establishment of the institution as a center of scientific research. Figuring prominently in the accomplishment of this vision was Tappan’s desire to establish an astronomical observatory.

According to Whitesell (1998), shortly after his inauguration Tappan established a relationship with Henry N. Walker, a prominent railroad lawyer. Through Walker a base of prospective donors from Detroit was established, including business men, politicians, other prominent citizens and scientific supporters. Commitments to a minimum of $10,000 were raised which enabled Tappan to proceed with his project in 1853. In recognition of these original donors the facility would be known as the Detroit Observatory (Figure 1). Beyond the academic research interests, however, it was Walker who foresaw the commercial benefits of establishing an observatory to provide accurate timekeeping to support rail and other commercial interests. As a result, he donated $4,000 for the acquisition of a meridian circle telescope (Whitesell 1998).

Tappan hired R.H. Bull of New York, who had a background in engineering and astronomy, to design the observatory. Henry N. Fitz of New York was contracted in 1853 to build a 12-5/8 inch diameter refracting telescope and mounting (Figure 2) for $6150 (Whitesell 1998). Tappan subsequently traveled to Europe to investigate purchase of a meridian telescope and sidereal clock. On his travels he met with J.F. Encke, of periodic comet fame, who referred him to Pistor and Martins for construction of a meridian circle and to M. Tiede for a sidereal clock. Encke and his assistant, Dr. Franz F. E. Brunnow, supervised the construction of the meridian circle for the University of Michigan. It was delivered in 1854 and today remains the oldest Pistor and Martins meridian circle (Figure 3) in the world still in its original mount (Whitesell, 1998).

Prior to 1854 about 25 observatories had been built in the United States, located primarily in eastern states. With the possible exception of Shelby College Observatory in Kentucky, which possessed a 7-1/2 inch diameter refractor, the Detroit Observatory was the western-most major observatory in the United States.

The relationship established with Brunnow during the procurement of the meridian circle led Tappan to recruit him for the position of observatory director. Brunnow, a favorite student of Encke, trained along side other distinguished astronomers, including Galle, Bremiker and D’Arrest (Whitesell 2003). Brunnow arrived in Ann Arbor in 1854 and became the school’s first faculty member to hold a doctorate degree (DOweb). In addition to a unique academic credential, Brunnow brought German astronomical methodology to America which was distinguished in its level of mathematical rigor. The University of Michigan became known as the place to study astronomy, being referred to as the Ann Arbor School of Astronomy (Whitesell, 1998 ). Brunnow’s impact as an educator extended beyond Michigan. His contributions to American higher education in astronomy have been compared to those of Agassiz in natural history (Bruce 1987).

Brunnow’s accomplishments at the Detroit Observatory in addition to instruction are likely equally enduring. His work included detailed studies of the motion of asteroids, double stars, timekeeping and accurate longitude determination of the observatory. He founded the publication Astronomical Notices, the first scholarly publication of the university (DOweb). Brunnow’s notable publications include Tables of Flora (1855) and Victoria (1859). In the earlier work he expressed his perspective regarding the pioneering and enduring impact of his work with the intent it would contribute to knowledge useful for hundreds of years (Brunnow 1855).

Among the first students of Brunnow at Detroit Observatory were Asaph Hall Sr., James Craig Watson and Cleveland Abbe. Hall studied under Brunnow in 1856 as a graduate student (Whitesell 2003). He had a distinguished career at the U.S. Naval Observatory and in 1877 discovered the moons of Mars. His son, Asaph Hall Jr., would come to the Detroit Observatory in 1892 as its fourth director, and during his tenure he would perform observations to determine the aberration constant of light (Hall 1902).

J. C. Watson was a favored student of Brunnow, in some instances being the sole participant in his class (Whitesell 1998). He eventually became the second director of the Detroit Observatory. He engendered professional controversy for his pursuit of business interests over academia and his claimed discovery of two intra-Mercurial planets during the total solar eclipse of July 1878 (Baum & Sheehan 1997). Despite these issues however, he was a significant contributor to astronomical science of his time. He is credited with discovering 22 asteroids, of which 21 were found at the Detroit Observatory between 1863 and 1877 (Whitesell 1998).

Cleveland Abbe achieved his M.A. in astronomy at Michigan in 1860 (Whitesell 2003). He became director of the Cincinnati Observatory, but focused on meteorology rather than astronomy. As the first scientific officer of a national weather service under the U.S. Army Signal Corps in 1871, he was instrumental in the creation of what today is the U.S. National Weather Service (NOAAweb).

The significant achievements of many astronomers educated at the Detroit Observatory prior to 1910, have been outlined by Whitesell (2003). Those listed are too numerous to describe in any detail here, but two in particular, J. M. Schaeberle, and H.D. Curtis, should be mentioned. While at the Detroit Observatory, Schaeberle discovered two significant comets, 1880 II and 1881 IV, although the 1880 comet was discovered with one of Schaeberle’s private instruments (Schaeberle 1880; Hussey 1924). Schaeberle also devised a portable long-focus camera for use on eclipse expeditions to image the solar corona which revealed a comet that would otherwise have been undetectable (Whitesell 2000). Heber Doust Curtis was classically educated at the University of Michigan. His later calling to astronomy would lead him to Lick Observatory. He is most recognized for his role in the “Great Debate” in 1920 with Harlow Shapley, presenting contrasting views of the “Scale of the Universe” (Marché & Linder 2000). In 1930 he returned to Michigan as the ninth director of the Detroit Observatory, where in the ensuing years, he was instrumental in the acquisition of new facilities.

Figure 2: Fitz Refractor 1998

Photo credit: Quinn Evans

Figure 3: Pistor & Martins Meridian Circle 1854

Photo Credit: Bentley Historical Library

20th Century Transformation

The 20th century was a physically transformative period for the observatory. In 1907 a 37.5 inch diameter mirror was purchased, the observatory was expanded in 1908 and the new instrument installed in 1911(Whitesell 1998). By 1912 however, the growing university began to encroach on the observatory and threaten observing conditions.

In the years that followed, the university expanded its astronomical facilities beyond the confines of the single campus observatory. A new student observatory was built atop Angell Hall. Through the support of R. P. Lamont, the Lamont-Hussey Observatory, was built in Bloemfontein, South Africa in 1928 (ASSAweb). In 1930, a private observatory was built near Lake Angelus, Michigan. Later incorporated by the university, it became known as the McMath-Hulbert Observatory. By 1931, these facilities were collectively known as “Observatories of the University of Michigan,” but the original building was still called the Detroit Observatory (Whitesell 1998).

Following World War II, facility expansion continued. The 36 inch Curtis Schmidt Telescope, was first located near Portage Lake, Michigan, and then relocated to Cerro Tololo Inter-American Observatory in Chile. In 1969 a 1.3 meter reflector was installed near Portage Lake. In 1955 the university created a radio astronomy observatory at Peach Mountain, Michigan. In 1958 a 26 meter dish was installed at this facility. Extragalactic object brightness variability on timescales as short as a few weeks was discovered here, and it remains active conducting studies of active galactic nuclei (UMAweb).

Photometry expert W.A. Hiltner returned to his alma mater in 1970 to become the final director of the Detroit Observatory. By then, the facility had little utility for research, and by 1976 all but the original 1854 structure was demolished. As a leader in the Association of Universities for Research in Astronomy (AURA) and influential in founding Cerro Tololo Inter-American Observatory, Hiltner brought experience and initiative for collaborative development of new facilities. Led by Hiltner, the University of Michigan collaborated with Dartmouth and Massachusetts Institute of Technology on the MDM Observatory at Kitt Peak, Arizona. The 1.3 meter instrument at Portage Lake was moved to McGraw-Hill Observatory on Kitt Peak in 1975, and a 2.4 meter telescope there was later named in his honor (Shectman 2000). By 1996 the university became a member of the consortium that built and now operates the 6.5 meter Magellan instruments at Las Campanas, Chile.


My first visit to the Detroit Observatory was in 1963 as a fourteen year old student, mentored by a Michigan astronomy undergraduate. The event afforded my first occasion to view through an observatory instrument. I remember seeing M57, M13, and Saturn through the Fitz refractor. I also recall the catwalks traversing the roof to connect the domes, and across which noted stellar spectroscopist D. B. McLaughlin and others scrambled to get a view of the goings-on during a “panty-raid” in the adjacent dormitory ( D. DeBruyn, interview 13 Mar 2009). During public nights in the early 1970’s I returned to the observatory a few times as it was falling into disrepair. I have only recently come to appreciate the significance of the Detroit Observatory and my improbable connections to some of the notable personalities associated with it: I have been a guest in the summer home of the Buhl family, one of the original Detroit Observatory donors (Whitesell 1998). H.D. Curtis and I share the same hometown (DOweb). I had the privilege of meeting W. A. Hiltner at Yerkes Observatory before he became the final Detroit Observatory director.


The original Detroit Observatory constructed at Tappan’s insistence still resides atop its hill (Figure 4.), now completely surrounded by University of Michigan hospitals and dormitories. Its work as a research facility is now done, but its spirit lives on in this educational institution and other great observatories. In 1973 it was placed on the National Register of Historic Places, and in the 1990’s the complete structure and instruments were meticulously restored. Today the Detroit Observatory is operated as a division of the Bentley Historical Library. The facility provides physical testimony to the vision of its early supporters, the educational precedents established here, and the continuing tradition of pioneering facilities and research in astronomy at the University of Michigan.

Figure 4: Detroit Observatory 1998

Photo credit: Dave Snyder, University Lowbrow Astronomers


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