Commissioning a laser metrology truss for active optics on the Large Binocular Telescope

Andrew Rakich, Heejoo Choi, Christian Veillet, John Hill, Olga Kuhn, Matthieu Bec, Yang Zhang, Trenton Brendel, Breann Sitarski, William Schoenell

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

2 Scopus citations


LBTO, in partnership with GMTO, has been developing a laser-truss-based metrology system for the active alignment of telescope main optical components. Positive initial results convinced LBTO to commence to develop a "pathfinder"integrated operational active-optics system at prime focus, utilizing this technological approach. The prime-focus active-optics system benefits LBTO directly in improved system performance and is also very useful for GMTO in developing and gaining experience with a critical technical component of the GMT Telescope Metrology System. This paper describes the current system, which is now commissioned and operates in support of regular scientific observing. Technical aspects unique to direct laser truss metrology, such as system stability, the effects of correlated and uncorrelated noise, and the benefits of channel redundancy, will be discussed. Commissioning results and general system performance will also be reported. The paper will conclude with a section discussing some of the unexpected insights and improvements that the TMS has brought about at LBT by enabling the measurement of "clean"aberration data for aberrations arising from shape change on the borosilicate primary mirrors.

Original languageEnglish (US)
Title of host publicationGround-Based and Airborne Telescopes IX
EditorsHeather K. Marshall, Jason Spyromilio, Tomonori Usuda
ISBN (Electronic)9781510653450
StatePublished - 2022
EventGround-Based and Airborne Telescopes IX 2022 - Montreal, United States
Duration: Jul 17 2022Jul 22 2022

Publication series

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


ConferenceGround-Based and Airborne Telescopes IX 2022
Country/TerritoryUnited States


  • 3-D Metrology
  • LBT
  • Laser Tracker
  • Optical Alignment
  • Telescope Alignment

ASJC Scopus subject areas

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


Dive into the research topics of 'Commissioning a laser metrology truss for active optics on the Large Binocular Telescope'. Together they form a unique fingerprint.

Cite this