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Proceedings Paper

Polishing and testing of the 3.4 m diameter f/1.5 primary mirror of the INO telescope
Author(s): Tapio Korhonen; Perttu Keinänen; Mikko Pasanen; Ahmad Darudi; Jonathan Maxwell
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Paper Abstract

Polishing and testing methods used in the manufacture of the 3.4 m primary mirror of the Iranian National Observatory (INO) telescope are described and the test results of the finished mirror are presented. Mirror lapping and polishing was performed using several rectangular non-rotating tools arranged in a linear array across the mirror radius. Each tool is equipped with two computer controlled force actuators for regulating the surface pressure and removal efficiency during the lapping and polishing operations. The same tool system was used from the lapping phase to the end of the final polishing. The principal optical test method was the interferometric Hartmann test with the aid of a two component null lens in the mirror center of curvature. Mirror measurements were made also with pentaprism test to verify its correct conic constant. The mirror was finished to extremely good surface accuracy and smoothness.

Paper Details

Date Published: 22 July 2016
PDF: 8 pages
Proc. SPIE 9912, Advances in Optical and Mechanical Technologies for Telescopes and Instrumentation II, 99120Q (22 July 2016); doi: 10.1117/12.2232691
Show Author Affiliations
Tapio Korhonen, Opteon Oy (Finland)
Perttu Keinänen, Opteon Oy (Finland)
Mikko Pasanen, Opteon Oy (Finland)
Ahmad Darudi, Univ. of Zanjan (Iran, Islamic Republic of)
Iranian National Observatory (Iran, Islamic Republic of)
Jonathan Maxwell, Consultant (United Kingdom)


Published in SPIE Proceedings Vol. 9912:
Advances in Optical and Mechanical Technologies for Telescopes and Instrumentation II
Ramón Navarro; James H. Burge, Editor(s)

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