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Proceedings Paper

Test And Evaluation Of The Hubble Space Telescope 2.4-meter Primary Mirror
Author(s): Lucian A. Montagnino
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Paper Abstract

Manufacture of the 2.4-meter diffraction-limited hyperboloidal primary mirror for the Hubble Space Telescope encompassed several state-of-the-art processes. These included computer-controlled polishing and interferometric test and evaluation. To advance the manufacturing processes to the 0.008μm rms surface figure level achieved on the primary mirror, full-aperture and sub-aperture interferometric test configurations were developed in conjunction with a precision interferogram analysis facility. Full-aperture interferometric testing of the uncoated mirror took place in air with the test chamber providing the necessary thermal and vibrational stability. A remotely-controlled, six-degree-of-freedom table was used to orient and position the mirror with respect to the fixed geometry metrology unit consisting of a Co-axial Reference Interferometer (CORI) and a reflective null corrector. The CORI generated a high quality spherical wavefront which, in turn, was converted to a hyperboloidal wavefront characteristic of the desired mirror surface by the reflective null corrector. Interferograms in the form of photographic negatives recorded the departures from the highly corrected null condition to provide surface contour and aberration data. The high spatial frequency surface defects, so important to the ultraviolet (UV) performance of the Space Telescope, were measured via sub-aperture interferometry. A laser interferoscope and precision test plates with reference surface radii appropriate to several zones on the primary mirror were employed to produce high fidelity measurements of "mid-frequency" defects at the 0.002μm rms level.

Paper Details

Date Published: 21 February 1986
PDF: 9 pages
Proc. SPIE 0571, Large Optics Technology, (21 February 1986); doi: 10.1117/12.950408
Show Author Affiliations
Lucian A. Montagnino, The Perkin-Elmer Corporation (United States)

Published in SPIE Proceedings Vol. 0571:
Large Optics Technology
Gregory M. Sanger, Editor(s)

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