Modern technologies of fabrication and testing of large convex secondary mirrors

Chang Jin Oh, Andrew E. Lowman, Matt Dubin, Greg Smith, Eric Frater, Chunyu Zhao, James H. Burge

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

9 Scopus citations

Abstract

Modern large telescopes such as TAO, LSST, TMT and EELT require 0.9m-4m monolithic convex secondary mirrors. The fabrication and testing of these large convex secondary mirrors of astronomical telescopes is getting challenging as the aperture of the mirror is getting bigger. The biggest challenge to fabricate these large convex aspheric mirrors is to measure the surface figure to a few nanometers, while maintaining the testing and fabrication cycle to be efficient to minimize the downtime. For the last a couple of decades there was huge advancement in the metrology and fabrication of large aspheric secondary mirrors. College of Optical Sciences in the University Arizona developed a full fabrication and metrology process with extremely high accuracy and efficiency for manufacturing the large convex secondary mirrors. In this paper modern metrology systems including Swing-Arm Optical Coordinate Measuring System (SOCMM) which is comparable to Interferometry and a Sub-aperture stitching interferometry scalable to a several meters have been presented. Also a Computer Controlled Fabrication Process which produces extremely fine surface figure and finish has been demonstrated. These most recent development has been applied to the fabrication and testing of 0.9m aspheric convex secondary mirror for the Tokyo Atacama Observatory's 6.5m telescope and the result has been presented.

Original languageEnglish (US)
Title of host publicationAdvances in Optical and Mechanical Technologies for Telescopes and Instrumentation II
EditorsRamon Navarro, James H. Burge
PublisherSPIE
ISBN (Electronic)9781510602038
DOIs
StatePublished - 2016
EventAdvances in Optical and Mechanical Technologies for Telescopes and Instrumentation II - Edinburgh, United Kingdom
Duration: Jun 26 2016Jul 1 2016

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
Volume9912
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X

Other

OtherAdvances in Optical and Mechanical Technologies for Telescopes and Instrumentation II
CountryUnited Kingdom
CityEdinburgh
Period6/26/167/1/16

Keywords

  • Aspheric
  • Convex
  • Fabrication
  • Secondary Mirror
  • Stitching Interferometry
  • Swingarm Optical CMM

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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