Dearborn Observatory

Coordinates: 42°03.4′N 87°40.5′W / 42.0567°N 87.6750°W / 42.0567; -87.6750
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Dearborn Observatory
The Dearborn Observatory in 2007
Alternative names2131 Tech Drive Edit this at Wikidata
Named afterMary Ann Haven Dearborn Edit this on Wikidata
OrganizationNorthwestern University
Observatory code 756 Edit this on Wikidata
LocationEvanston, Illinois, U.S.A.
Coordinates42°03.4′N 87°40.5′W / 42.0567°N 87.6750°W / 42.0567; -87.6750
Altitude195 meters (640 feet)
Established1889 (first founding 1862)
Website[1]
Telescopes
Dearborn Telescope469.9 millimetres (18.50 in) refractor
Dearborn Observatory is located in the United States
Dearborn Observatory
Location of Dearborn Observatory
[edit on Wikidata]

The Dearborn Observatory is an

Technological Institute.[1]

The 1888 observatory is the second Dearborn Observatory, the first had been erected on the Old 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 the Adler Planetarium since 1929.[2] The 18 1/2 was used to discover Sirius B, a companion to the brightest star in the night sky.

Summary

The telescope was established at Douglass 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 to Adler 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 the

Chicago 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]

History

The history of the Dearborn Observatory coincides with the founding of the

Frederick Augustus Porter Barnard, the chancellor of the University of Mississippi (later president of Columbia University), who hoped to found an observatory with the new lens. He commissioned the renowned firm of Alvan Clark & Sons of Cambridge, Massachusetts, to construct the lens. However, the American Civil War began before the lens could be delivered to Mississippi
. The lens therefore remained in the Clark's shop in Cambridge, where it was eventually put up for sale.

The lens was initially intended for Harvard University, but was bought instead by Chicagoan Thomas Hoyne, a founding member of the Chicago Astronomical Society, for the sum of $11,187. The Chicago Astronomical Society intended the lens for the Old University of Chicago (a precursor to the current University 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 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.

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

George Washington Hough
.

Photo of the Dearborn Telescope
A photo of the Dearborn Telescope pointed at the Orion Nebula

The close affiliation between Dearborn Observatory and the Chicago Astronomical Society continued until, following the

Technological 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.

Sirius B discovery

On January 31, 1862, American telescope-maker and astronomer Alvan 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) aperture great 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]

Timeline

  • 1862: Clark discovers Sirius B, splitting the brightest star in the sky with brand new 18 1/2 inch refractor[6]
  • 1864–1886: Used at Douglass Park in Chicago, Illinois.[2]
  • 1889: The 18 1/2 is moved to Evanston, Illinois[2]
  • 1911: The objective is moved to a new mounting and tube (old tube and mount saved)[2]

See also

References

  1. ^ a b c "Dearborn Observatory". Northwestern Architecture. Northwestern University Archives.
  2. ^ a b c d e f g h i j k l m Deller, Craig (1999). "The Conservation of the Historic Dearborn Telescope" (PDF). WAG Postprints. Wooden Artifacts Group of the American Institute for Conservation.
  3. ISBN 9780521242561
    .
  4. ^ a b "History of the Chicago Astronomical Society". Archived from the original on 2007-07-21. Retrieved 2007-08-07.
  5. ^ Arthur Herbert Wilde (1905). Northwestern University: a history, 1855–1905. The University Publishing Co. p. 315.
  6. ^
    Bibcode:1877AReg...15..186F
    .
  7. ^ Craig, John; Gravatt, William; Slater, Thomas; Rennie, George. "The Craig Telescope". craig-telescope.co.uk. Retrieved 3 January 2011.
  8. ^ Appletons' annual cyclopaedia and register of important events of the year: 1862. New York: D. Appleton & Company. 1863. p. 176.

External links

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