1 July 1990 System for precise temperature sensing and thermal control of borosilicate honeycomb mirrors during polishing and testing
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Abstract
The Steward Observatory Mirror Laboratory has implemented a large borosilicate honeycomb telescope mirror polishing system in which thermal distortion is reduced to negligible levels by maintaining the glass in an isothermal state to within 0.1 C. Testing of the polished surface is conducted in air, using a laser and interferometer mounted above the mirror; the control of refractive index variation in the laser's light-path entails that the air also be isothermal, to within 0.2 C. Thermocouples are used as sensors in the polishing room, in air ducts, and on the mirror. Measurements are made to an accuracy of 0.005 C at the rate of one thermocouple/sec.
© (1990) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Michael Lloyd-Hart, "System for precise temperature sensing and thermal control of borosilicate honeycomb mirrors during polishing and testing", Proc. SPIE 1236, Advanced Technology Optical Telescopes IV, (1 July 1990); doi: 10.1117/12.19249; https://doi.org/10.1117/12.19249
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