File:OpticalGlass 020.jpg
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| Description |
English: The large disk in the center of the photo was one of three twelve-inch planes in NBS' possession. They were rated as one-tenth of a wavelength of a true plane, but in equal temperature two of them showed practically no error. Disks for five-inch objectives with twenty and one-half inch focal lengths were cut from squares as shown in the top of the picture. Although of such short focal length to aperture both chromatic and spherical abberations were fully corrected. The curves used were an adaption of the Tuttron formula and the glass was of NBS crown and flint. Also shown in the image: smaller samples of NBS optical class and workmanship. |
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| Source | National Institute of Standards and Technology | |||
| Author | National Institute of Standards and Technology | |||
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This image is in the public domain in the United States because it is a work of the United States Federal Government, specifically an employee of the National Institute of Standards and Technology, under the terms of Title 17, Chapter 1, Section 105 of the US Code.
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| Date/Time | Thumbnail | Dimensions | User | Comment | |
|---|---|---|---|---|---|
| current | 19:09, 7 March 2014 | | 5,738 × 4,494 (23.11 MB) | NISTResearchLibrary (talk | contribs) |
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