Meridian Circle

This instrument was installed in the new observatory at Vassar College in Poughkeepsie, New York, in 1865, and used by Maria Mitchell, her students, and successors. It is marked "Wm. J. Young Philadelphia, Pa." The telescope has a clear aperture of 4 inches, and a focal length of 5 feet. The circles at either end of the axis measure 30 inches in diameter. One is finely graduated to 3" of arc, and read by vernier; the other is used simply as a finder. Vassar College donated it to the Smithsonian in 1980, along with the observer's couch and the apparatus used to reverse the telescope.
D. J. Warner, "William J. Young: From Craft to Industry in a Skilled Trade," Pennsylvania History 52 (1985): 53-68.
Currently not on view
Object Name
transit, astronomical
astronomical transit
meridian circle
date made
ca 1865
Young, William J.
Physical Description
brass (overall material)
overall: 26 in x 41 in x 60 in; 66.04 cm x 104.14 cm x 152.4 cm
place made
United States: Pennsylvania, Philadelphia
ID Number
accession number
catalog number
See more items in
Medicine and Science: Physical Sciences
Science & Mathematics
Data Source
National Museum of American History, Kenneth E. Behring Center


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