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Proceedings Paper

Ray-tracing for coordinate knowledge in the JWST Integrated Science Instrument Module
Author(s): Derek Sabatke; Joseph Sullivan; Scott Rohrbach; David Kubalak
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Paper Abstract

Optical alignment and testing of the Integrated Science Instrument Module of the James Webb Space Telescope is underway. We describe the Optical Telescope Element Simulator used to feed the science instruments with point images of precisely known location and chief ray pointing, at appropriate wavelengths and flux levels, in vacuum and at operating temperature. The simulator's capabilities include a number of devices for in situ monitoring of source flux, wavefront error, pupil illumination, image position and chief ray angle. Taken together, these functions become a fascinating example of how the first order properties and constructs of an optical design (coordinate systems, image surface and pupil location) acquire measurable meaning in a real system. We illustrate these functions with experimental data, and describe the ray tracing system used to provide both pointing control during operation and analysis support subsequently. Prescription management takes the form of optimization and fitting. Our core tools employ a matrix/vector ray tracing model which proves broadly useful in optical engineering problems. We spell out its mathematical basis, and illustrate its use in ray tracing plane mirror systems relevant to optical metrology such as a pentaprism and corner cube.

Paper Details

Date Published: 17 December 2014
PDF: 27 pages
Proc. SPIE 9293, International Optical Design Conference 2014, 929306 (17 December 2014); doi: 10.1117/12.2074373
Show Author Affiliations
Derek Sabatke, Ball Aerospace & Technologies Corp. (United States)
Joseph Sullivan, Ball Aerospace & Technologies Corp. (United States)
Scott Rohrbach, NASA Goddard Space Flight Ctr. (United States)
David Kubalak, NASA Goddard Space Flight Ctr. (United States)

Published in SPIE Proceedings Vol. 9293:
International Optical Design Conference 2014
Mariana Figueiro; Scott Lerner; Julius Muschaweck; John Rogers, Editor(s)

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