 The Dearborn Observatory in 2007 | |||
| Alternative names | 2131 Tech Drive | ||
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| Named after | Mary Ann Haven Dearborn | ||
| Organization | Northwestern University | ||
| Observatory code | 756 | ||
| Location | Evanston, Illinois, U.S.A. | ||
| Coordinates | 42°03.4′N87°40.5′W / 42.0567°N 87.6750°W /42.0567; -87.6750 | ||
| Altitude | 195 meters (640 feet) | ||
| Established | 1889 (first founding 1862) | ||
| Website | [1] | ||
| Telescopes | |||
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  Location of Dearborn Observatory | |||
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TheDearborn Observatory is anastronomical observatory located on theEvanston campus ofNorthwestern University. The observatory was originally constructed in 1888, through an agreement between the university and the Chicago Astronomical Society. In the summer of 1939, Dearborn Observatory had to be moved to make way for the construction of theTechnological Institute.[1]
The 1888 observatory is the second Dearborn Observatory, the first had been erected on theOld University of Chicago campus.
The observatory is home to the Dearborn 18 1/2 inch refractor, which was the largest telescope in the United States in the late 1860s.[2] Due to the complicated history, it was operated from a different site at that time, and the original tube and mounting is at theAdler Planetarium since 1929.[2] The 18 1/2 was used to discoverSirius B, a companion to the brightest star in thenight sky.
The telescope was established atDouglass Park in a 90 foot tall dome of the old University of Chicago.[2] It was operated by the old University until about 1886 when ownership passed to the Chicago Astronomical Society in 1887.[2] It was moved to Northwestern University at Evanston by 1889.[2] CAS still supported operations of the observatory jointly with a university benefactor at the new location.[2] The Chicago Astronomical Society did not transfer ownership to Northwestern University until 1929, however.[2]
In 1911 the original tube and mounting were replaced, and eventually donated toAdler Planetarium in 1929 by the Chicago Astronomical Society.[2]
The early records of the telescope before 1871 are more limited because documents were destroyed in theChicago Fire of 1871.[2]
The telescope was surpassed by the 26-inch (66 cm)Great Refactor installed at the United States Naval Observatory in 1873, then located at Foggy Bottom.[3]
The history of the Dearborn Observatory coincides with the founding of theChicago Astronomical Society in 1862.[4] The society heard of the 1861 construction of a 469.9 millimetres (18.50 in) lens for a telescope, which made it, at the time, the largestrefracting telescope in the world. The lens had been commissioned byFrederick Augustus Porter Barnard, the chancellor of theUniversity of Mississippi, and later president ofColumbia University, who hoped to found an observatory with the new lens. He commissioned the renowned firm ofAlvan Clark & Sons ofCambridge, Massachusetts, to construct the lens. However, theAmerican Civil War began before the lens could be delivered toMississippi. The lens therefore remained in the Clark's shop in Cambridge, where it was eventually put up for sale.
The lens was initially intended forHarvard University, but was bought instead byChicagoanThomas Hoyne, a founding member of the Chicago Astronomical Society, for the sum of $11,187. The Chicago Astronomical Society intended the lens for theOld University of Chicago (a precursor to the currentUniversity of Chicago) and a tower was constructed on Cottage Grove Avenue around the lens. The structure was named the "Dearborn Observatory" in honor of Mary Ann Haven Dearborn, the deceased wife ofJ. Young Scammon, principal benefactor of the project. Construction of the observatory began in 1863, and the original Dearborn Observatory was completed two years later. The Observatory was managed by the Old University of Chicago for many years, however financial struggle caused it to declare bankruptcy in 1881, and the Chicago Astronomical Society had to do battle in the courts to successfully establish their title to the Dearborn instruments & library.
In 1887, the Chicago Astronomical Society signed a deal with Northwestern University to bring the telescope to Evanston, and a new observatory was built on the Evanston campus to house the telescope. Funding for the project was provided by Astronomical Society member and Northwestern TrusteeJames B. Hobbs. The new observatory was designed by architectural firmCobb and Frost and constructed oflimestone in theRichardsonian Romanesque style.[1] The cornerstone for the building was laid on June 21, 1888, and the dedication took place on June 19, 1889.[5] The first director of the observatory at Northwestern wasastronomerGeorge Washington Hough.
The close affiliation between Dearborn Observatory and the Chicago Astronomical Society continued until, following theWall Street crash of 1929, the Society encountered financial hardship and found it too expensive to maintain the observatory and its equipment. On April 30, 1930, the Chicago Astronomical Society formally relinquished its title to the observatory to Northwestern University, on the condition that the Observatory be open to the public without cost.[4] In 1911, Northwestern decided that the lens needed a more modern mounting, and the original tube and mount were removed. In 1929, these pieces were placed on permanent loan to the new Adler Planetarium, and installed on the planetarium's exhibit floor. The 470 millimetres (19 in) lens has remained at Northwestern.[2] In the summer of 1939, the Dearborn Observatory building had to be moved 200 metres (660 ft) southeast to its present location to make way for the construction of theTechnological Institute. The latest addition to the observatory was an 11.6 metres (38 ft) aluminum dome, added in 1997.[1] The observatory underwent extensive renovations to both the interior and exterior in the summer of 2015.
Northwestern University's astronomy department resided in the offices of Dearborn until 2013, when most of the department moved into a newly renovated wing of the Technological Institute. The telescope is still used by astronomy classes and is open to the public every Friday night. The director of Dearborn Observatory is Professor Michael Smutko.
On January 31, 1862, American telescope-maker and astronomerAlvan Graham Clark first observed the faint companion, which is now called Sirius B, or affectionately "the Pup".[6] This happened during testing of an 18.5-inch (470 mm) aperturegreat refractor telescope for Dearborn Observatory, which was one of the largest refracting telescope lens in existence at the time, and the largest telescope in the United States.[7] Sirius B's sighting was confirmed on March 8, 1862, with smaller telescopes.[8]
{{cite book}}:ISBN / Date incompatibility (help)Located in:Evanston IL andvarious other locations | |||||||
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