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Proceedings Paper

Corning 7972 ULE material for segmented and large monolithic mirror blanks
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Paper Abstract

Ultra-Low Expansion (ULE®) glass has been and continues to be a significant material for astronomical applications. With a nominal composition of 7 wt. %TiO2 in SiO2, Corning Code 7972 ULE® has a mean room temperature coefficient of thermal expansion (CTE) of 0 ± 30 ppb/°C with a typical CTE range of less than 15 ppb/°C, properties vital to the manufacture of high resolution optics requiring extreme thermal stability. Combined with lightweighting techniques developed at Corning during the past 30 years, ULE® has been successfully employed for numerous monolithic and lightweight mirror applications including the 2.4 meter Hubble Space Telescope lightweight primary mirror, the Airborne Laser (ABL) primary mirrors, and most recently the Discovery Channel Telescope 4 meter mirror blank. ULE® maintains its strong candidacy for future ELT applications. Recent challenges in mirror surface specifications and the development of alternative material choices calls for a comparison with ULE®. The objective of this article is to review ULE® properties and manufacturing capabilities, and to compare relevant material properties to those of alternative material options, thus allowing designers to properly execute material selection. Finally, recent development efforts directed toward improving ULE® will be discussed.

Paper Details

Date Published: 6 July 2006
PDF: 8 pages
Proc. SPIE 6273, Optomechanical Technologies for Astronomy, 627302 (6 July 2006); doi: 10.1117/12.672059
Show Author Affiliations
Robert Sabia, Corning Inc. (United States)
Mary J. Edwards, Corning Inc. (United States)
Randy VanBrocklin, Corning Inc. (United States)
Bruce Wells, Corning Inc. (United States)


Published in SPIE Proceedings Vol. 6273:
Optomechanical Technologies for Astronomy
Eli Atad-Ettedgui; Joseph Antebi; Dietrich Lemke, Editor(s)

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