Accuracy of laser tracker measurements of the GMT 8.4 m off-axis mirror segments

Tom L. Zobrist, James H. Burge, Hubert M. Martin

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

16 Scopus citations

Abstract

We have developed a metrology system that is capable of measuring rough ground and polished surfaces alike, has limited sensitivity to the nominal surface shape, and can accommodate surfaces up to 8.4 m in diameter. The system couples a commercial laser tracker with an advanced calibration technique and a system of stability references to mitigate numerous error sources. This system was built to guide loose abrasive grinding and initial polishing of the offaxis primary mirror segments for the Giant Magellan Telescope (GMT), and is also being used to guide the fabrication of the Large Synoptic Survey Telescope primary and tertiary mirrors. In addition to guiding fabrication, the system also works as a verification test for the GMT principal optical interferometric test of the polished mirror segment to corroborate the measurement in several low-order aberrations. A quantitative assessment of the system accuracy is presented, along with measurement results for GMT, including a comparison to the optical interferometric test of the polished surface.

Original languageEnglish (US)
Title of host publicationModern Technologies in Space- and Ground-Based Telescopes and Instrumentation
DOIs
StatePublished - Sep 23 2010
EventModern Technologies in Space- and Ground-Based Telescopes and Instrumentation - San Diego, CA, United States
Duration: Jun 27 2010Jul 2 2010

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
Volume7739
ISSN (Print)0277-786X

Other

OtherModern Technologies in Space- and Ground-Based Telescopes and Instrumentation
CountryUnited States
CitySan Diego, CA
Period6/27/107/2/10

Keywords

  • Aspheres
  • Laser metrology
  • Optical fabrication
  • Optical testing
  • Telescopes

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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  • Cite this

    Zobrist, T. L., Burge, J. H., & Martin, H. M. (2010). Accuracy of laser tracker measurements of the GMT 8.4 m off-axis mirror segments. In Modern Technologies in Space- and Ground-Based Telescopes and Instrumentation [77390S] (Proceedings of SPIE - The International Society for Optical Engineering; Vol. 7739). https://doi.org/10.1117/12.856520