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

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

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

47 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
Volume1236 pt 2
ISBN (Print)081940280X
Publication statusPublished - 1990
EventAdvanced Technology Optical Telescopes IV - Tuscon, AZ, USA
Duration: Feb 12 1990Feb 16 1990


OtherAdvanced Technology Optical Telescopes IV
CityTuscon, AZ, USA


ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Condensed Matter Physics

Cite this

Martin, H. M., Anderson, D. S., Angel, J. R. P., Nagel, R. H., West, S. C., & Young, R. S. (1990). Progress in the stressed-lap polishing of a 1.8-m f/1 mirror. In L. D. Barr (Ed.), Proceedings of SPIE - The International Society for Optical Engineering (Vol. 1236 pt 2, pp. 682-690). Publ by Int Soc for Optical Engineering.