The Dearborn Observatory is an
astronomical observatory
An observatory is a location used for observing terrestrial, marine, or celestial events. Astronomy, climatology/meteorology, geophysical, oceanography and volcanology are examples of disciplines for which observatories have been constructed. H ...
located on the
Evanston campus of
Northwestern University
Northwestern University is a private research university in Evanston, Illinois. Founded in 1851, Northwestern is the oldest chartered university in Illinois and is ranked among the most prestigious academic institutions in the world.
Chart ...
. 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
Technological Institute.
The 1888 observatory is the second Dearborn Observatory, the first had been erected on the
Old University of Chicago
The Old University of Chicago was the legal name given in 1890 to the University of Chicago's first incorporation.
The school, founded in 1856 by Baptist church leaders, was originally called the "University of Chicago" (or, interchangeably, "Ch ...
campus.
The observatory is home 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
Adler Planetarium
The Adler Planetarium is a public museum in Chicago, Illinois, dedicated to astronomy and astrophysics. It was founded in 1930 by local businessman Max Adler. Located on the northeastern tip of Northerly Island on Lake Michigan in the city, th ...
since 1929.
The 18 1/2 was used to discover
Sirius B
Sirius is the brightest star in the night sky. Its name is derived from the Greek word , or , meaning 'glowing' or 'scorching'. The star is designated α Canis Majoris, Latinized to Alpha Canis Majoris, and abbreviated Alpha CM ...
, a companion to the brightest star in the
night sky
The night sky is the nighttime appearance of celestial objects like stars, planets, and the Moon, which are visible in a clear sky between sunset and sunrise, when the Sun is below the horizon.
Natural light sources in a night sky inc ...
. The 18 1/2 was the largest telescope in the Americas for many years until the U.S. Naval Observatory's 26-inch refractor.
Summary
The telescope was established at
Douglass Park
Douglass Park is a part of the Chicago Park District on the West Side of Chicago, Illinois. Established in 1869 and initially named South Park,Graf, John, ''Chicago's Parks'' Arcadia Publishing, 2000, p. 11., . its are in the North Lawndal ...
in a 90 foot tall dome of the old University of Chicago.
It was operated by the old University until about 1886 and 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 with a University benefactor at the new location.
The Chicago Astronomical Society did not transfer ownership to Northwestern University until 1929, however.
In 1911 the original tube and mounting were replaced, and eventually donated to
Adler Planetarium
The Adler Planetarium is a public museum in Chicago, Illinois, dedicated to astronomy and astrophysics. It was founded in 1930 by local businessman Max Adler. Located on the northeastern tip of Northerly Island on Lake Michigan in the city, th ...
in 1929 by the Chicago Astronomical Society.
The early records of the telescope before 1871 are more limited because documents were destroyed in the
Chicago Fire of 1871
The Great Chicago Fire was a conflagration that burned in the American city of Chicago during October 8–10, 1871. The fire killed approximately 300 people, destroyed roughly of the city including over 17,000 structures, and left more than 10 ...
.
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.
History
The history of the Dearborn Observatory coincides with the founding of the
Chicago Astronomical Society
(''City in a Garden''); I Will
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in 1862.
The society heard of the 1861 construction of a lens for a telescope, which made it, at the time, the largest
refracting telescope
A refracting telescope (also called a refractor) is a type of optical telescope that uses a lens as its objective to form an image (also referred to a dioptric telescope). The refracting telescope design was originally used in spyglasses and ...
in the world. The lens had been commissioned by
Frederick Augustus Porter Barnard
Frederick Augustus Porter Barnard (May 5, 1809 – April 27, 1889) was an American academic and educator who served as the 10th President of Columbia University. Born in Sheffield, Massachusetts, he graduated from Yale University in 1828 and serv ...
, the chancellor of the
University of Mississippi
The University of Mississippi ( byname Ole Miss) is a public research university that is located adjacent to Oxford, Mississippi, and has a medical center in Jackson. It is Mississippi's oldest public university and its largest by enrollment. ...
(later president of
Columbia University
Columbia University (also known as Columbia, and officially as Columbia University in the City of New York) is a private research university in New York City. Established in 1754 as King's College on the grounds of Trinity Church in Manha ...
), who hoped to found an observatory with the new lens. He commissioned the renowned firm of
Alvan Clark & Sons
Alvan Clark & Sons was an American maker of optics that became famous for crafting lenses for some of the largest refracting telescopes of the 19th and early 20th centuries. Founded in 1846 in Cambridgeport, Massachusetts, by Alvan Clark (1804&nd ...
of
Cambridge, Massachusetts
Cambridge ( ) is a city in Middlesex County, Massachusetts, United States. As part of the Greater Boston, Boston metropolitan area, the cities population of the 2020 United States Census, 2020 U.S. census was 118,403, making it the fourth most ...
, to construct the lens. However, the
American Civil War
The American Civil War (April 12, 1861 – May 26, 1865; also known by other names) was a civil war in the United States. It was fought between the Union ("the North") and the Confederacy ("the South"), the latter formed by state ...
began before the lens could be delivered to
Mississippi
Mississippi () is a state in the Southeastern region of the United States, bordered to the north by Tennessee; to the east by Alabama; to the south by the Gulf of Mexico; to the southwest by Louisiana; and to the northwest by Arkansas. Mis ...
. 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
Harvard University is a private Ivy League research university in Cambridge, Massachusetts. Founded in 1636 as Harvard College and named for its first benefactor, the Puritan clergyman John Harvard, it is the oldest institution of high ...
, but was bought instead by
Chicago
(''City in a Garden''); I Will
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an
Thomas Hoyne
His Honor, the Mayor, Thomas Hoyne, Esquire (February 11, 1817July 27, 1883) was elected Mayor of Chicago in 1876, but his election was later declared null and void by a Circuit Court. Prior to 1876, Hoyne had led a political career in which h ...
, 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
The Old University of Chicago was the legal name given in 1890 to the University of Chicago's first incorporation.
The school, founded in 1856 by Baptist church leaders, was originally called the "University of Chicago" (or, interchangeably, "Ch ...
(a precursor to the current
University of Chicago
The University of Chicago (UChicago, Chicago, U of C, or UChi) is a private university, private research university in Chicago, Illinois. Its main campus is located in Chicago's Hyde Park, Chicago, Hyde Park neighborhood. The University of Chic ...
) 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
Northwestern University is a private research university in Evanston, Illinois. Founded in 1851, Northwestern is the oldest chartered university in Illinois and is ranked among the most prestigious academic institutions in the world.
Chart ...
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
James B. Hobbs. The new observatory was designed by architectural firm
Cobb and Frost and constructed of
limestone
Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms wh ...
in the
Richardsonian Romanesque
Richardsonian Romanesque is a style of Romanesque Revival architecture named after the American architect Henry Hobson Richardson (1838–1886). The revival style incorporates 11th and 12th century southern French, Spanish, and Italian Romanesq ...
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
astronomer
An astronomer is a scientist in the field of astronomy who focuses their studies on a specific question or field outside the scope of Earth. They observe astronomical objects such as stars, planets, moons, comets and galaxies – in either o ...
George Washington Hough.
The close affiliation between Dearborn Observatory and the Chicago Astronomical Society continued until, following the
Wall Street Crash of 1929
The Wall Street Crash of 1929, also known as the Great Crash, was a major American stock market crash that occurred in the autumn of 1929. It started in September and ended late in October, when share prices on the New York Stock Exchange coll ...
, 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
The Adler Planetarium is a public museum in Chicago, Illinois, dedicated to astronomy and astrophysics. It was founded in 1930 by local businessman Max Adler. Located on the northeastern tip of Northerly Island on Lake Michigan in the city, th ...
, and installed on the planetarium's exhibit floor. The lens has remained at Northwestern.
In the summer of 1939, the Dearborn Observatory building had to be moved southeast to its present location to make way for the construction of the
Technological Institute. The latest addition to the observatory was an aluminum dome, added in 1997.
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 current director of Dearborn Observatory is Professor Michael Smutko.
Sirius B discovery
On January 31, 1862, American telescope-maker and astronomer
Alvan Graham Clark
Alvan Graham Clark (July 10, 1832 – June 9, 1897) was an American astronomer and telescope-maker.
Biography
Alvan Graham Clark was born in Fall River, Massachusetts, the son of Alvan Clark, founder of Alvan Clark & Sons.
On January 31, 1862, ...
first observed the faint companion, which is now called Sirius B, or affectionately "the Pup".
This happened during testing of an aperture
great refractor
Great refractor refers to a large telescope with a lens, usually the largest refractor at an observatory with an equatorial mount. The preeminence and success of this style in observational astronomy defines an era in modern telescopy in the 19t ...
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.
Timeline
* 1862: Clark discovers Sirius B, splitting the brightest star in the sky with brand new 18 1/2 inch refractor
* 1864–1886: Used at Douglass Park in Chicago, Illinois.
* 1889: The 18 1/2 is moved to Evanston, Illinois
* 1911: The objective is moved to a new mounting and tube (old tube and mount saved)
See also
*
Corralitos Observatory
Corralitos Observatory was an astronomical observatory located in the Rough and Ready Hills approximately west of Las Cruces, New Mexico. It was formally dedicated on October 12, 1965, serving as a remote station of Dearborn Observatory, Nort ...
*
Lindheimer Astrophysical Research Center
Lindheimer Astrophysical Research Center was an astronomical observatory used for teaching and research, located on the Evanston, Illinois campus of Northwestern University. The structure was built in 1966 and was demolished in 1995.
History
T ...
*
List of largest optical refracting telescopes
Refracting telescopes use a lens to focus light. The largest refracting telescope in the world is the Yerkes Observatory 40 inch (102 cm) refractor, used for astronomical and scientific observation for over a century. The Swedish 1-m ...
*
List of the largest optical telescopes in North America#Biggest telescopes in 1900
References
External links
Dearborn Observatory Records, Northwestern University Archives, Evanston, IllinoisNU Astronomy and Astrophysics group
{{Authority control
Infrastructure completed in 1889
Astronomical observatories in Illinois
Northwestern University campus
1889 establishments in Illinois