428:, 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. 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. 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 the
383:) 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 of J. 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.
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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
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in a 90 foot tall dome of the old
University of Chicago. It was operated by the old University until about 1886 when ownership passed to the Chicago Astronomical Society in 1887. It was moved to Northwestern University at Evanston by 1889. CAS still supported operations of the observatory jointly
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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 Trustee
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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. Due to the complicated history, it was operated from a different site at that time, and the original tube and mounting is at the
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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. Sirius B's sighting was confirmed on March 8, 1862, with smaller telescopes.
256:. 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 the
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432:. The latest addition to the observatory was an 11.6 metres (38 ft) aluminum dome, added in 1997. The observatory underwent extensive renovations to both the interior and exterior in the summer of 2015.
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style. The cornerstone for the building was laid on June 21, 1888, and the dedication took place on June 19, 1889. The first director of the observatory at
Northwestern was
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first observed the faint companion, which is now called Sirius B, or affectionately "the Pup". This happened during testing of an 18.5-inch (470 mm) aperture
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with a
University benefactor at the new location. The Chicago Astronomical Society did not transfer ownership to Northwestern University until 1929, however.
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in 1862. 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 largest
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1862: Clark discovers Sirius B, splitting the brightest star in the sky with brand new 18 1/2 inch refractor
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The 1888 observatory is the second
Dearborn Observatory, the first had been erected on the
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List of the largest optical telescopes in North
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installed at the United States Naval Observatory in 1873, then located at Foggy Bottom.
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1911: The objective is moved to a new mounting and tube (old tube and mount saved)
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Appletons' annual cyclopaedia and register of important events of the year: 1862
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In 1911 the original tube and mounting were replaced, and eventually donated to
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The history of the Dearborn Observatory coincides with the founding of the
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Craig, John; Gravatt, William; Slater, Thomas; Rennie, George.
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Flammarion, Camille (August 1877). "The Companion of Sirius".
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On January 31, 1862, American telescope-maker and astronomer
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Northwestern Journal of Technology and Intellectual Property
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727:. New York: D. Appleton & Company. 1863. p. 176.
391:. The new observatory was designed by architectural firm
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The telescope was surpassed by the 26-inch (66 cm)
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1864–1886: Used at Douglass Park in Chicago, Illinois.
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Northwestern University Institute for Policy Research
571:"The Conservation of the Historic Dearborn Telescope"
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436:Dearborn Observatory is Professor Michael Smutko.
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417:A photo of the Dearborn Telescope pointed at the
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333:in the world. The lens had been commissioned by
468:1889: The 18 1/2 is moved to Evanston, Illinois
747:"Circumstances of the day deliver Observatory"
16:Astronomical observatory in Evanston, Illinois
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648:Northwestern University: a history, 1855–1905
621:"History of the Chicago Astronomical Society"
497:List of largest optical refracting telescopes
303:in 1929 by the Chicago Astronomical Society.
357:began before the lens could be delivered to
275:since 1929. The 18 1/2 was used to discover
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651:. The University Publishing Co. p.
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533:. Northwestern University Archives.
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185:469.9 millimetres (18.50 in)
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840:various other locations
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430:Technological Institute
408:George Washington Hough
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254:Northwestern University
72:Northwestern University
1242:The Daily Northwestern
1215:Land of Lincoln Trophy
918:Segal Design Institute
569:Deller, Craig (1999).
527:"Dearborn Observatory"
482:Corralitos Observatory
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347:Alvan Clark & Sons
40:Alternative names
1249:North by Northwestern
1145:Northwestern Wildcats
933:Northwestern Medicine
702:craig-telescope.co.uk
698:"The Craig Telescope"
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381:University of Chicago
151:195 meters (640 feet)
79:Observatory code
979:Dearborn Observatory
923:McGaw Medical Center
898:Professional Studies
331:refracting telescope
308:Chicago Fire of 1871
242:Dearborn Observatory
23:Dearborn Observatory
683:1877AReg...15..186F
395:and constructed of
343:Columbia University
132:42.0567°N 87.6750°W
128: /
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1225:Willie the Wildcat
1165:Women's Basketball
1107:Northwestern Qatar
1044:University Library
1024:Shakespeare Garden
780:2010-06-04 at the
764:2008-10-06 at the
752:2013-12-18 at the
446:Alvan Graham Clark
440:Sirius B discovery
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366:Harvard University
355:American Civil War
182:Dearborn Telescope
102:Evanston, Illinois
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1319:Go U Northwestern
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854:Arts and Sciences
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1314:Dolphin Show
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1268:TriQuarterly
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1190:Men's soccer
1180:Field Hockey
1121:
1112:Media Majlis
1100:Qatar Campus
989:The Lakefill
978:
974:Block Museum
828:
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68:Organization
1471:Outer space
1459:Spaceflight
1339:Waa-Mu Show
1123:The Daily Q
1009:Old College
889:Theological
871:Engineering
834:Evanston IL
359:Mississippi
156:Established
135: /
110:Coordinates
53:Named after
19:Observatory
1517:Categories
1370:John Evans
1365:Presidents
1297:Traditions
1210:Ryan Field
1129:Studio 20Q
1065:Residences
969:Residences
876:Journalism
866:Management
829:Located in
631:2007-08-07
508:References
405:astronomer
252:campus of
173:Telescopes
1495:Education
1435:Astronomy
1395:Endowment
1309:Dillo Day
1138:Athletics
1060:Buildings
964:Buildings
848:Academics
707:3 January
397:limestone
370:Chicagoan
281:night sky
187:refractor
123:87°40.5′W
120:42°03.4′N
1423:Illinois
1391:: 21,208
1389:Students
1195:Softball
1170:Baseball
1155:Football
1034:The Rock
906:Research
884:Medicine
778:Archived
762:Archived
750:Archived
476:See also
457:Timeline
277:Sirius B
267:campus.
250:Evanston
148:Altitude
104:, U.S.A.
98:Location
1507:Science
1409:Portals
1383:Founded
1360:Faculty
1324:History
1150:Big Ten
679:Bibcode
399:in the
321:History
287:Summary
164:Website
1385:: 1851
1355:Alumni
1348:People
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244:is an
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1447:Stars
1234:Media
861:Music
574:(PDF)
229:[
1274:WNUR
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240:The
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