Progress toward making lightweight 8-m mirrors of short focal length

James Roger P. Angel; Warren B. Davison; John M. Hill; Edward J. Mannery; Hubert M. Martin

doi:10.1117/12.19273

1 July 1990 Progress toward making lightweight 8-m mirrors of short focal length

James Roger P. Angel, Warren B. Davison, John M. Hill, Edward J. Mannery, Hubert M. Martin

Proceedings Volume 1236, Advanced Technology Optical Telescopes IV; (1990) https://doi.org/10.1117/12.19273
Event: SPIE Astronomical Telescopes and Instrumentation for the 21st Century, 1990, Tucson, AZ, United States

Abstract

A technique has been developed for casting glass in the form of a honeycomb structure possessing good stiffness despite its low weight, and facilitating thermal control via forced ventilation of the honeycomb cells. To date, 3.5 m diameter mirrors of this type have been successfully cast; fully 8 m diameter mirrors are expected to be cast by 1992. No mirror of diameter as large as 8 m has ever been polished, however, and the difficulties which will be encountered shall be compounded by the shorter focal lengths required for advanced telescopic optics. A novel method, designated 'stressed lap polishing', has been developed to address these problems.

Citation Download Citation

James Roger P. Angel, Warren B. Davison, John M. Hill, Edward J. Mannery, and Hubert M. Martin "Progress toward making lightweight 8-m mirrors of short focal length", Proc. SPIE 1236, Advanced Technology Optical Telescopes IV, (1 July 1990); https://doi.org/10.1117/12.19273

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