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Proceedings Paper

SALT segmented primary mirror: inductive edge sensors
Author(s): Hitesh Gajjar; John Menzies; David Buckley; Christian Neel; Philippe Parbaud; Stéphane Royet
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Paper Abstract

The development of an inductive edge sensor is in process for the control of the Southern African Large Telescope’s (SALT)1 segmented mirror primary. The original capacitive edge sensing system was not capable of maintaining the figure of the primary mirror due to excessive noise and a severe sensitivity to humidity despite exhaustive attempts at characterisation1. The prototype of the inductive edge sensor has progressed to a mature industrialised version that is in the process of being installed and commissioned on SALT. The performance of the sensor in response to temperature and RH is very good with a maximum error of 10nm typical after temperature compensation. The noise and control characteristics of the array have been simulated in order to establish the maximum cumulative error and error rate tolerable for the SALT specific case. It has been established through simulation that over the expected 5 day alignment cycle, a maximum cumulative error of 30nm can be tolerated.

Paper Details

Date Published: 22 July 2014
PDF: 10 pages
Proc. SPIE 9145, Ground-based and Airborne Telescopes V, 91454X (22 July 2014); doi: 10.1117/12.2056217
Show Author Affiliations
Hitesh Gajjar, South African Astronomical Observatory (South Africa)
John Menzies, South African Astronomical Observatory (South Africa)
David Buckley, South African Astronomical Observatory (South Africa)
Christian Neel, Fogale Nanotech (France)
Philippe Parbaud, Fogale Nanotech (France)
Stéphane Royet, Fogale Nanotech (France)

Published in SPIE Proceedings Vol. 9145:
Ground-based and Airborne Telescopes V
Larry M. Stepp; Roberto Gilmozzi; Helen J. Hall, Editor(s)

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