Alignment of 4-mirror Wide Field Corrector for the Hobby-Eberly Telescope

Chang Jin Oh, Eric H. Frater, Laura Coyle, Matt Dubin, Andrew Lowman, Chunyu Zhao, James H. Burge

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

1 Scopus citations


The Hobby-Eberly Telescope (HET) Wide Field Corrector (WFC) is a four-mirror optical system which corrects for aberrations from the 10-m segmented spherical primary mirror. The WFC mirror alignments must meet particularly tight tolerances for the system to meet performance requirements. The system uses 1-m class highly aspheric mirrors, which precludes conventional alignment methods. For the WFC system alignment a "center reference fixture" has been used as the reference for each mirror's vertex and optical axis. The center reference fixtures have both a CGH and sphere mounted retroreflector (SMR) nests. The CGH is aligned to the mirror's optical axis to provide a reference for mirror decenter and tilt. The vertex of each mirror is registered to the SMR nests on the center reference fixtures using a laser tracker. The spacing between the mirror vertices is measured during the system alignment using these SMR nest locations to determine the vertex locations. In this paper the procedures and results from creating and characterizing these center reference fixtures are presented. As a verification of proposed alignment methods the results from their application in the WFC system alignment are also presented.

Original languageEnglish (US)
Title of host publicationOptical System Alignment, Tolerancing, and Verification VII
ISBN (Print)9780819496942
StatePublished - 2013
EventOptical System Alignment, Tolerancing, and Verification VII - San Diego, CA, United States
Duration: Aug 25 2013Aug 26 2013

Publication series

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


OtherOptical System Alignment, Tolerancing, and Verification VII
Country/TerritoryUnited States
CitySan Diego, CA


  • Alignment
  • Aspheric mirror
  • Center reference fixture
  • Hobby-eberly telescope wide field corrector

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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