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Samuel Pierpont Langley, the founding directory of the Smithsonian Astrophysical Observatory, was keen to map the intensity of solar radiation at different points in the spectrum, and this project continued long after Langley’s death in 1906. Charles Greeley Abbot unveiled his silver-disk pyrheliometer in around 1910 and, in time, Andrew Kramer, the SAO instrument maker, made nearly 100 copies for observers around the world.
Ref: C. G. Abbot, “The Astrophysical Observatory of the Smithsonian Institution,” Astronomical Society of the Pacific Leaflet 16 (1947).
Currently not on view
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overall: 15 1/4 in x 3 1/8 in x 5 1/2 in; 38.735 cm x 7.9375 cm x 13.97 cm
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Medicine and Science: Physical Sciences
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National Museum of American History
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