Progress in the stressed-lap polishing of a 1.8-m f/1 mirror

H. M. Martin, D. S. Anderson, J. R.P. Angel, R. H. Nagel, S. C. West, R. S. Young

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

53 Scopus citations


We are in the process of polishing a 1.8-m f/1 ellipsoid with an actively stressed lap. As a preliminary exercise, we have polished the mirror as a sphere using a rigid subdiameter lap. The overall surface error was 25 nm rms, and the surface met a specification corresponding to 1/8-arcsec image quality. A stressed lap 600 mm in diameter was designed and built to polish the mirror as an f/1 ellipsoid. It consists of an aluminum disk which changes shape continuously under the influence of 12 moment-generating actuators. These actuators are programmed to produce the shape changes necessary to make the lap fit the mirror surface as it moves across that surface and rotates. In this paper we describe the principles and design of the lap, test results, and progress to date in polishing the 1.8-m mirror.

Original languageEnglish (US)
Title of host publicationProceedings of SPIE - The International Society for Optical Engineering
EditorsLawrence D. Barr
PublisherPubl by Int Soc for Optical Engineering
Number of pages9
ISBN (Print)081940280X
StatePublished - 1990
EventAdvanced Technology Optical Telescopes IV - Tuscon, AZ, USA
Duration: Feb 12 1990Feb 16 1990

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
Volume1236 pt 2
ISSN (Print)0277-786X


OtherAdvanced Technology Optical Telescopes IV
CityTuscon, AZ, USA

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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