Polishing and testing of the 3.4 m diameter f/1.5 primary mirror of the INO telescope

Tapio Korhonen; Perttu Keinänen; Mikko Pasanen; Ahmad Darudi; Jonathan Maxwell

doi:10.1117/12.2232691

22 July 2016 Polishing and testing of the 3.4 m diameter f/1.5 primary mirror of the INO telescope

Tapio Korhonen, Perttu Keinänen, Mikko Pasanen, Ahmad Darudi, Jonathan Maxwell

Proceedings Volume 9912, Advances in Optical and Mechanical Technologies for Telescopes and Instrumentation II; 99120Q (2016) https://doi.org/10.1117/12.2232691
Event: SPIE Astronomical Telescopes + Instrumentation, 2016, Edinburgh, United Kingdom

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.

Citation Download Citation

Tapio Korhonen, Perttu Keinänen, Mikko Pasanen, Ahmad Darudi, and Jonathan Maxwell "Polishing and testing of the 3.4 m diameter f/1.5 primary mirror of the INO telescope", Proc. SPIE 9912, Advances in Optical and Mechanical Technologies for Telescopes and Instrumentation II, 99120Q (22 July 2016); https://doi.org/10.1117/12.2232691

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available