Skip to main content

Dearborn Observatory



The Chicago Astronomical Society was founded in 1862 by a group of Chicago business and civic leaders who wanted to establish an observatory in Chicago. Aquaria, natural history museums, and observatories were considered educational and cultural concomitants of growing scientific inquiry and industrial technology, and their numbers grew substantially in the mid-nineteenth century.

By January 1863, sufficient funds had been raised through the sale of memberships in the Society to enable a committee to investigate various lens and purchase a suitable one. What was, at the time, the world's largest refracting lens became available as a result of the Civil War. Just prior to the War, Alvan Clark, America's foremost lensmaker, had ground an 18½ inch refractor for F.A.P. Barnard of the University of Mississippi. However, hostilities made delivery of the lens impossible, and the Chicago group was able to purchase it at a price of $11,187 including mounting.

The Society contracted with the original University of Chicago in July 1863 to house the observatory. Society member J. Young Scammon bore the cost of constructing the observatory tower and dome with the stipulation that it be named for his late wife, Mary Ann Haven Dearborn. W.W. Boyington designed both the tower and the dome. Construction began at 3400 S. Cottage Grove Avenue in the autumn of 1863 and the dome was completed in October, 1865. The lens arrived in Chicago on March 25, 1866, was mounted by Clark, and became operational on April 11, 1866. In addition to the equatorial, the Society was able to purchase a meridian circle with a $5000 donation from Walter S. Gurnee, Society member and former mayor of Chicago. Additional small instruments and books were purchased with donations from other Society members.

While the building was being completed, the Astronomical Society perfected its organization. The Society incorporated and elected its first officers during November and December 1865. At the same time a search was begun for a professional astronomer to direct the work of the observatory. On December 28, 1865, Truman H. Safford accepted an appointment as Director of the Observatory and professor of astronomy in the University of Chicago.

In addition to conducting celestial observations, the observatory initiated Chicago's first standard time service. The Chicago fire of October 8-9, 1871, brought research to a halt. The observatory was not damaged by the fire, but many of its most committed patrons, including J. Young Scammon who had been providing the director's salary, suffered severe financial losses as a result of the fire.

When it became clear that he would be receiving no salary for the foreseeable future, Safford requested and received a leave to join the U.S. Coast and Geodetic Survey. At the end of the leave, he accepted a position at Williams College instead of returning to Chicago. The Society's Executive Committee appointed Safford's assistant, Elias Colbert as Acting Director. Colbert was unable to engage in much research between 1872 and 1875, since he spent the majority of his time seeking funds to rehabilitate the observatory, the most pressing need being a replacement for the dome, which had proved highly unreliable. In 1875 Colbert reestablished the standard time service, and the $500 in revenue it generated comprised the bulk of his salary.

In 1876 Colbert announced his intention to resign as Acting Director. A talented amateur astronomer, S.W. Burnham, was appointed non-salaried Acting Director, but when it became clear later that year that Safford would not be returning, Colbert again assumed supervision of the Observatory. Colbert was successful in raising enough money to install a new dome and bring Alvan Clark to Chicago to recondition the lens.

In May 1879, Colbert retired and George Washington Hough was named Director. Hough launched an extensive program of observations, although he did not begin receiving a regular salary until 1881.

In June 1881, the virtually bankrupt University of Chicago's creditors moved to foreclose. There was concern that the Astronomical Society might lose title to the observatory's lens, meridian circle, other instruments, and library, but in 1886 the Cook County Circuit Court ruled that the scientific instruments and books could not be seized as payment for the university's debts. The observatory building, however, was ruled part of the university and liable to sale with other of the university's real estate holdings. In July 1887 the Society was informed that it had to vacate the building by October. Society board member and Northwestern University Trustee Oliver Horton proposed that the Observatory be moved to Northwestern's Evanston campus. An agreement between the Society and Northwestern was signed in August 1887, stipulating that Northwestern would construct a suitable building for the telescope and a house for the Director. The Director was to have the rank of professor in the university and his salary would be paid by the university. Northwestern would hold title to the building, while the Society would retain title to all the scientific instruments. The Astronomical Society would also retain its autonomy.

Hough supervised the removal of all instruments to temporary quarters in Evanston. University Trustee James B. Hobbs provided funds for a new building which was begun in June 1888 and dedicated June 1889. The total cost for a new building, designed by Cobb and Frost was $25,000. Hough recommenced observations with the 181/2 inch refractor in September 1889.

Hough continued as Director until his death on January 1, 1909. In September, Philip Fox was named Director. Fox instituted many improvements in the observatory equipment, most notably the replacement of mechanical recording devices with photographic techniques. Fox also built the first spectrograph for the 181/2 inch refractor. In 1910, the original mounting and telescope drive were replaced with a modern mounting and electric drive.

Prior to Fox's arrival the research carried out at Dearborn had been reported in scientific journals, including the Astronomical Journal and Popular Astronomy. Fox initiated the Annals of Dearborn Observatory in 1915 as a means of systematically reporting observations, editing the first two volumes of the Annals himself.

Fox resigned in 1929 to become the first Director of the Adler Planetarium. In April 1929 the Chicago Astronomical Society relinquished title to the telescope, meridian circle, and all scientific instruments to Northwestern, thus ending its sixty-six year association with the Dearborn Observatory. Fox was replaced by the assistant astronomer Oliver J. Lee, who served as Director from 1929 until 1947.

The most notable event that occurred during Lee's tenure was the relocation of the observatory building in 1939, necessitated by the construction of the Technological Institute. The twenty-five hundred ton building was jacked up, placed on rails, and pulled 664 feet south-southeast of its original site at the rate of twenty inches per minute. The observatory was out of service from June 18 to November 13, 1939. Aside from the need to recalculate the Observatory's precise longitude and latitude, the move had no adverse effects.

Lee retired in 1947 and was replaced by Kaj Strand. Strand served as Director for eleven years and maintained an active observational program. Upon Strand's resignation in 1958, the Directorship remained vacant for almost a year until J. Allen Hynek accepted the post. Hynek updated the observatory's facilities, pioneering the use of image-orthicon viewing systems, and the use of computers to analyze results. He also used the Dearborn facilities for several NASA projects. Under Hynek, the university opened an observatory in Organ Pass, New Mexico, and in 1967, the university dedicated the Lindheimer Astronomical Research Center. The new facility, with 40 inch and 16 inch reflecting telescopes and a wide range of computerized apparatus supplanted Dearborn as the university's primary astronomical facility. However, Dearborn's 181/2 inch refractor remained an active teaching instrument and provided free public viewings and tours. In 1975 Hynek retired and John Bahng became Director of Astrophysical Studies including responsibility for Dearborn.

From 1866 to 1967 the Dearborn telescope was used for a wide variety of observational projects. Under Safford and Colbert, the Observatory was used primarily in star cataloging projects. Dearborn contributed to the Astronomische Gesellschaft catalog until the Chicago fire limited all observations.

Perhaps Dearborn's most significant contribution was in the area of double star research. The existence of pairs of stars located close enough to each other that their gravities had an effect on each other's motion had been theorized by the middle of the nineteenth century, but prior to the grinding of the 181/2 inch refractor, no telescope had provided sufficient resolution to actually see a double star. During the testing of the newly ground lens in 1861, Alvan Clark made the first observation of the companion star of Sirius. After the lens was installed in Chicago, it was used by Burnham and extensively by Hough to study double stars. The first two volumes of the Annals of the Dearborn Observatory reported several hundred double stars discovered by Burnham, Hough, and Fox.

Hough carried on extensive observations of the planet Jupiter and was considered the foremost authority on the behavior of Jupiter's bands and spots. Fox carried out extensive research on stellar parallax, or the apparent displacement in direction of position of an object when observed from two points. Lee did considerable observation of Eros, an asteroid that periodically orbits closer to Earth than Mars does, and on huge, forming red stars.

Additional information on the Chicago Astronomical Society and its relationship to the Dearborn Observatory may be found in the holdings of the Chicago Historical Society. The Chicago Historical Society holds a manuscript history and minutes of the Society from 1862 - 1903, as well as the Society's Annual Reports, 1880 - 1887, and H.C. Rainey's two volume history of the Society.

Found in 5 Collections and/or Records:

Dearborn Observatory Records

Identifier: 29/2
Abstract Records of Dearborn Observatory, built in 1865 by the Chicago Astronomical Society and the University of Chicago and in 1889 moved to Northwestern University's Evanston campus. Dearborn Observatory was a significant contributor in the area of double star research. The records consist almost entirely of observational data gathered by astronomers using Dearborn's 18-1/2 inch refracting telescope or its meridian circle, calculations performed on the data, and the results of such...
Dates: 1863-1967

Philip Fox (1878 - 1944) Papers

Identifier: 29/3
Abstract The Philip Fox papers, comprising one box, include correspondence, astronomical notes and calculations, notes and drafts of publications, and lists compiled by Fox of outstanding scientists.The general correspondence covers the years from 1904 to 1941. Of interest are the four letters written in 1909 urging the purchase of the Simon Newcomb Library for the Astronomy Department at Northwestern. The standard equinox correspondence records Fox's interest in 1915 in establishing such a...
Dates: 1904-1941

George Washington Hough (1836-1909) Papers

Identifier: 29/1
Abstract The George Washington Hough Papers, spanning the years 1855 to 1909, comprise seven boxes and five Gaylord oversize folders. They are arranged in seven subseries: diaries and notebooks; correspondence; teaching material; research material; lectures; manuscripts and drafts; and published works. Included are diaries Hough kept as a student, lecture notes, professional and personal correspondence, class books, graded student exams, observational records, drawings of and data pertaining to...
Dates: 1855-1909

Oliver J. Lee (1881-1964) Papers

Identifier: 29/5

The papers of Oliver J. Lee fill one half-size box. They consist of several biographical accounts, a small amount of correspondence, a poem, a tribute to his predecessor, Philip Fox, and reprints of his articles.

Dates: 1930-1964

Truman H. Safford (1836-1901) Papers

Identifier: 29/4
Abstract Astronomer Truman Safford was the first director of the Dearborn Observatory (in its old location on the South Side of Chicago, before it was moved in 1889 to Northwestern University). The records consist mainly of notebooks in which he recorded observations, calculations and notes. Materials include Safford's teaching files from the first University of Chicago, astronomical observations, computations regarding celestial objects, extracts from astronomical catalogs and two manuscripts. One...
Dates: 1850-1871

Additional filters:

Astronomy--Observations 4
Astronomers 3
Astronomical observatories--United States 3
Astronomy--Study and teaching 2
Stars--Observations 2