Optical metrology for two large highly aspheric telescope mirrors

S. C. West, J. H. Burge, R. S. Young, D. S. Anderson, C. Murgiuc, D. A. Ketelsen, H. M. Martin

Research output: Contribution to journalArticlepeer-review

10 Scopus citations


We describe a relatively simple, but highly effective, approach to the system design and alignment of an all-refractive Offner null corrector and phase-measuring Shack cube interferometer. In addition we outline procedures for fabricating and testing the optical components. Allowable errors for all parameters are determined by a tolerance analysis that separates axisymmetric and residual figure errors. An open construction optics frame provides a high degree of metering flexibility by incorporating simple kinematic mounts that provide adjustment of each lens while also allowing the lens to be removed and replaced with < 2-pLm absolute repeatability. Nonaxisymmetric alignment errors are removed by rotating the optics on a high-precision bearing. Axial spacings are measured with contact transducers attached to both ends of an Invar metering rod. Two completed systems have guided the stressed-lap polishing of 1.8-m f/ 1.0 and 3.5-m f/ 1.5 aspheric mirrors.

Original languageEnglish (US)
Pages (from-to)7191-7197
Number of pages7
JournalApplied optics
Issue number34
StatePublished - Dec 1992


  • Interferometry
  • Metrology
  • Null correctors
  • Optical testing
  • Polishing

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Engineering (miscellaneous)
  • Electrical and Electronic Engineering


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