Polarizing Solar Eyepiece

Polarizing Solar Eyepiece

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Several sorts of solar eyepieces came into use in the second half of the nineteenth century. This example, from the U.S. Naval Observatory, is based on the polarizing form produced by Merz in Munich; an account and illustration of that German instrument can be seen in The Sun (1880) written by the American astronomer, Charles A. Young.
The “John A. Brashear / Allegheny, Pa. No. 16” inscription is that of John A. Brashear (1840-1920), a Pennsylvania machinist who moved to Allegheny in 1886, and who showed “a modification of the Merz-Young polarizing helioscope, less liable to breakage than the old form” at the 1887 meeting of the American Association for the Advancement of Science. The firm became The John A. Brashear Co., Ltd. in 1901.
Ref: Len Jensen, “Two Rare Solar Eyepieces,” Journal of the Antique Telescope Society 2 (1992): 3-5.
“Proceedings of the American Association,” Science 10 (1887): 85.
Currently not on view
Object Name
eyepiece, telescope
date made
late 1880s
Brashear, John A.
place made
United States: Pennsylvania, Pittsburgh, Allegheny City
overall: 3 3/4 in x 3 5/8 in x 7 1/4 in; 9.525 cm x 9.2075 cm x 18.415 cm
ID Number
accession number
catalog number
Credit Line
U.S. Naval Observatory
Science & Scientific Instruments
See more items in
Medicine and Science: Physical Sciences
Data Source
National Museum of American History
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