Micrometer

Micrometer

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Description
This is a micrometer designed for measuring celestial photographs. The “L. M. R. No 3 1870” inscription refers to Lewis Morris Rutherfurd (1816-1892), a wealthy and prominent New Yorker who made important contributions to astronomical photography and spectroscopy.
Here, the photographic plate is held on the horizontal bed, illuminated from below, and read from above through a microscope. For measures in rectangular coordinates, the microscope is moved by two perpendicular micrometer screws. For position angles, the plate and its bed are rotated, and the angular distance read on a graduated circle.
This example was made from Rutherfurd’s designs, and under his supervision, for the U.S. Coast Survey. It was originally used to measure photographs taken during the solar eclipse of August 7, 1869. Charles S. Peirce would later use it to compare the lengths of varies centimeter scales.
Ref: Deborah Jean Warner, “Lewis M. Rutherfurd: Pioneer Astronomical Photographer and Spectroscopist,” Technology and Culture 12 (1971): 190-216.
Location
Currently not on view
Object Name
Micrometer
date made
1870
maker
Rutherfurd, Lewis Morris
place made
United States: New York, New York City
Measurements
overall: 15 3/4 in x 16 1/4 in x 11 in; 40.005 cm x 41.275 cm x 27.94 cm
ID Number
PH.322304
catalog number
322304
accession number
247805
subject
Science & Scientific Instruments
See more items in
Medicine and Science: Physical Sciences
Data Source
National Museum of American History
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