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  Northwestern University
November 9, 2000
Vol. 16, No. 8  
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Dearborn Observatory
Workhorses were used in 1939 to move the Dearborn Observatory
[click image to enlarge]

Circumstances of the day deliver Observatory

Dearborn Observatory — one of the oldest landmarks on the Evanston campus — traces its origins to pre-Civil War Mississippi.

In 1859 F. A. P. Barnard, president of the University of Mississippi, commissioned construction of the observatory lens that eventually made its way to Northwestern.

The University of Mississippi had commissioned lensmaker Alvin Clark of Cambridge, Mass., to craft 18-1/2-inch glass blanks made in Birmingham, England, into a lens that would surpass the 15-inch lenses at the Harvard College Observatory in Cambridge and the Pulkova Observatory in Russia.

The lens, to be installed in an observatory structure erected at the Oxford, Miss., campus, promised an image 50 percent brighter than Harvard and Pulkova, the two largest refractors in the world at the time.

The lens would become the largest in the world, a distinction it held for many years.

But Mississippi’s agreement with Clark fell through when the Civil War broke out. The lens never made it to the Mississippi observatory, which eventually became the home of the school’s chancellor.

The lens made it way to Chicago when the newly formed Chicago Astronomical Society bought the lens from Clark for $18,187 in 1863. The society did not have an observatory, but it promised the use of the lens to the original University of Chicago, which agreed to build an observatory.

Chicago lawyer J. Y. Scammon donated the money for the observatory tower and dome at 3400 S. Cottage Grove, Chicago. The lens was installed in 1864, and the facility was named for Scammon’s late wife, Mary Ann Haven Dearborn, a descendant of Revolutionary War hero Henry Dearborn, for whom Fort Dearborn was named.

The astronomical society decided to move the telescope to Northwestern after the bankruptcy of the original University of Chicago in 1887. It was installed in the new Dearborn Observatory on the Evanston campus in a building donated by J. B. Hobbs.

The Dearborn Observatory was built in 1889on what is now the site of the Technological Institute — at the south end of Noyes Street east of Sheridan Road. It was designed by Henry Ives Cubb, who had designed the Newberry Library in Chicago.

Dearborn's refracting telescope was used by generations of astronomers to study the planets, discover hundreds of double stars and nebulae, and measure the precise rate of continental drift. Professor George Washington Hough studied the planet Jupiter and became known as "Jupiter" Hough.

To make way for construction of the Technological Institute in 1939, the observatory was moved 664 feet southeast to its current location.

The herculean feat used 26 jackscrews to move the 2,500-ton stone structure. Horses were used with tractors to turn the winches.

The last major change to the observatory took place three years ago when a new aluminum dome was installed atop the structure. The dome -- eight tons and 38 feet in diameter -- was installed with a huge crane that placed the dome on the observatory in just a few minutes’ time.

The new dome and other renovations to the observatory have enabled scientists and students to continue to use the telescope for teaching and research at a time when much astronomical study takes place on computer screens that are thousands of miles away from telescopes in remote sites or in outer space.

The new dome was installed in August 1997. The new top was fabricated by Observa-DOME Laboratories in Jackson, Miss., completing a Mississippi-Northwestern connection that began 138 years earlier.

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Northwestern University, Sesquicentennial Office, 1936 Sheridan Road, 3rd floor, Illinois 60208;
Monica Metzler, Director. 847-491-1500; . Last revised 03/09/01.
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