Stitching of off-axis sub-aperture null measurements of an aspheric surface

Chunyu Zhao, James H. Burge

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

55 Scopus citations


Optical testing of a large convex aspheric surface, such as the secondary of a Ritchey-Chretien telescope, can be performed with a Fizeau interferometer that utilizes subaperture aspheric reference plates, each providing a null test of a subaperture of the larger mirror. The subaperture data can be combined or stitched together to create a map of the full surface. The region of the secondary mirror surface under test in each sub-aperture is an off-axis segment of the parent aspheric surface, therefore, the Fizeau reference requires a non-axi-symmetric aspheric surface to match it. Misalignment of the Fizeau reference relative to the parent in each sub-aperture will then result in aberrations in the measurements other than the ordinary terms of piston and tilt. When stitching sub-aperture measurements together, the apparent aberrations due to the null lens misalignment need to be fitted and subtracted. This paper presents an algorithm to perform this particular type of stitching.

Original languageEnglish (US)
Title of host publicationInterferometry XIV
Subtitle of host publicationTechniques and Analysis
StatePublished - 2008
EventInterferometry XIV: Techniques and Analysis - San Diego, CA, United States
Duration: Aug 11 2008Aug 13 2008

Publication series

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


OtherInterferometry XIV: Techniques and Analysis
Country/TerritoryUnited States
CitySan Diego, CA


  • Aspheric optics
  • Optical testing
  • Stitching

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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