Measurement of large on-axis and off-axis mirrors using software configurable optical test system (SCOTS)

Andrew E. Lowman, Greg A. Smith, Lori Harrison, Steven C. West, Chang Jin Oh

Research output: Chapter in Book/Report/Conference proceedingConference contribution

7 Scopus citations

Abstract

One of the major challenges of optical fabrication is measurement of the surface when first polished out, before its figure is within the capture range of interferometry. A high dynamic range instrument with good accuracy is needed to efficiently guide the processing. Our approach is to use the Software Configurable Optical Test System (SCOTS), a deflectometry technique that uses a camera and liquid crystal display to measure the surface slope. We describe the use of SCOTS in the fabrication of a 6.5 m on-axis mirror and an 8.4 m off-axis mirror segment (Giant Magellan Telescope primary). SCOTS has the dynamic range to measure high slope errors early in the mirror figuring process, with sufficient accuracy to corroborate later interferometric measurements. Accurately measuring low order figure errors with SCOTS requires careful calibration of the system geometry. Details of the data collection and processing, and comparison to interferometry measurements are presented.

Original languageEnglish (US)
Title of host publicationAdvances in Optical and Mechanical Technologies for Telescopes and Instrumentation III
EditorsRoland Geyl, Ramon Navarro
PublisherSPIE
ISBN (Print)9781510619654
DOIs
StatePublished - Jan 1 2018
EventAdvances in Optical and Mechanical Technologies for Telescopes and Instrumentation III 2018 - Austin, United States
Duration: Jun 10 2018Jun 15 2018

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
Volume10706
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X

Other

OtherAdvances in Optical and Mechanical Technologies for Telescopes and Instrumentation III 2018
CountryUnited States
CityAustin
Period6/10/186/15/18

Keywords

  • Aspheric
  • Deflectometry
  • GMT
  • Metrology
  • Telescope

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering

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