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Flower and Cook Observatory Records, 1875 - 1987


5 Cubic ft.
Prepared by Kaiyi Chen
September 2001

Access to collections is granted in accordance with the Protocols for the University Archives and Records Center.


Transferred to the University Archives in 1999.



The collection has been arranged alphabetically by subject.



In 1897, the University of Pennsylvania formally dedicated its observatory on a 100-acre farm bequeathed by Mr. Reese Wall Flower, whose great uncle, George Graham, had been an astronomer in London. The initial establishment consisted of three buildings on the Flower farm in Upper Darby and was equipped with an 18" aperture Warner and Swasey refractor. One of the three buildings, devoted to precise positioning and time observations of stars, also contained several astronomical clocks, a prism transit, a meridian circle and later, also a zenith telescope.

Meanwhile, Gustavus Wynne Cook, an avid amateur astronomer and wealthy Philadelphia businessman, established an observatory in his own home. When he moved to an estate in Wynnewood during the depression, he constructed two buildings to accommodate his hobby. Equipped with a 28.5" reflector (J. W. Fecker Company), a unique 15" siderostat refractor, and a wide assortment of camera and telescopes, his installation became one of the best equipped amateur observatories in the world. When Mr. Cook died in 1940, he left all his astronomical instruments to the University of Pennsylvania.

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Photograph of Flower Observatory and Director's Residence, ca. 1897-1899

In the late 1940s, Charles P. Olivier, then Chairman of the Astronomy Department and Director of the Flower Observatory, urged the University administration to purchase a plot of land in Willistown Township, Chester County, bounded by Providence Road and Warren Avenue. The Flower Observatory site was abandoned, its equipment stored and the proceeds from the sale to be used for the construction of a new observatory at the site near Providence Road.

In 1954, simultaneous with the completion of the new Physical Science Building (later called the David Rittenhouse Laboratory), an on-campus observatory was established on the rooftop of the building. In 1956, a new off-campus Flower and Cook Observatory was finally constructed with funds from the sale of the Flower Observatory property.

Photograph of Flower Observatory and Director's Residence, 1956


The collection includes a fairly complete set of Flower and Cook Observatory publication reprints from 1929 to 1987; a publishing file related to C. P. Olivier's work on EZ Aquilae; notebooks and log books kept by Olivier, R. Stanley Alexander, and several other astronomers from 1933 to 1951; records of the program of resolving time by the Pierce Photometer from 1958 to 1975; teaching material of two astronomy courses; and the file of a grant project financed by the National Science Foundation in the 1960s.

Also included are two memorabilia items originally belonging to Olivier and two sets of photographs--one of the solar eclipse observation in 1932 and the other of Frank Bradshaw Wood (a Penn faculty member being the 1957 research scholar in Astronomy at the Australian National University, Canberra) showing his work at the Mount Stromlo Observatory.

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