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Proceedings Paper

Assembly, Alignment, And Cold Focus Test Methods Utilized On Claes Optics
Author(s): Juan C. Dawson; John F Kauer; Charles M Reilly; Bruce C. Steakley
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Paper Abstract

The CLAES Telescope and Spectrometer were aligned as separate units. The optical interface between the two units is at the intermediate Lyot stop, where close angular and centering tolerances are required, with control by the use of matched machined tooling. In the alignme-L. of the Spectrometer, all optical components were centered to the chief ray using centering targets to align the optical components. The initial assembly was made at room temperature, and tested at 20K. One key reason for this testing is that the refractive indices for ZnS and ZnSe are not known below 90K, and therefore the exact location of the image plane is not known. The tests at 20K established the location of the image plane. A beam of collimated carbon-dioxide laser power illuminates the cryogenically cooled Spectrometer or the CLAES Instrument along the optical axis. The collimation of the beam is adjustable in small increments; the beam is scanned over the edges of the individual detectors creating edge scans that were used to determine where the image plane is located. Given the offset from exact collimation of the input beam, the corrections required to locate the image at the detector plane are computed. To determine "best focus", the inverse of the slopes of the edge-traces are plotted. Data obtained on both sides of best focus is plotted; the curves look like parabolas with upward arms. The minimum of this curve is defined as the location of the image plane. Shims that compensate for the focus errors are cut to the correct thickness, and installed. In addition to setting focus, the cryogenic tests were used to determine stability of the optics over the specified environment, and blur size measurements were performed at operational temperatures.

Paper Details

Date Published: 27 April 1988
PDF: 8 pages
Proc. SPIE 0973, Cryogenic Optical Systems and Instruments III, (27 April 1988); doi: 10.1117/12.948388
Show Author Affiliations
Juan C. Dawson, Lockheed Palo Alto Research Laboratories (United States)
John F Kauer, Lockheed Palo Alto Research Laboratories (United States)
Charles M Reilly, Lockheed Palo Alto Research Laboratories (United States)
Bruce C. Steakley, Lockheed Palo Alto Research Laboratories (United States)

Published in SPIE Proceedings Vol. 0973:
Cryogenic Optical Systems and Instruments III
Ramsey K. Melugin; Warren G. Pierce, Editor(s)

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