HARMONI is an integral field spectrograph working in the visible and near-infrared (0.47 to 2.45 μm) and will provide the E-ELT’s core spectroscopic capability, starting at first light. To minimise the thermal background it will be a cryogenic instrument with the optomechanics inside the cryostat having an operating temperature of 130K. We have designed three different thermally compensating lens mounts and have started analysing their performance by measuring the position of a glass blank relative to the mount to look for any displacement and tilt as it cooled down to operating temperature. The suitability of a commercial iris shutter for use in HARMONI is also assessed and found to work down to 120K, though further work is needed to prove it is reliable enough to be included in HARMONI, including an accelerated lifetime test.

Date Published: 18 July 2014
PDF: 11 pages
Proc. SPIE 9147, Ground-based and Airborne Instrumentation for Astronomy V, 91479M (18 July 2014); doi: 10.1117/12.2056340

Published in SPIE Proceedings Vol. 9147:
Ground-based and Airborne Instrumentation for Astronomy V
Suzanne K. Ramsay; Ian S. McLean; Hideki Takami, Editor(s)