Share Email Print
cover

Proceedings Paper

Pre-construction progress of giant steerable science mirror for TMT
Format Member Price Non-Member Price
PDF $14.40 $18.00
cover GOOD NEWS! Your organization subscribes to the SPIE Digital Library. You may be able to download this paper for free. Check Access

Paper Abstract

The Changchun Institute of Optics, Fine Mechanics and Physics (CIOMP) team is developing the Giant Steerable Science Mirror (GSSM) for Thirty Meter Telescope (TMT) which will enter the preliminary design phase in 2016. The GSSM is the tertiary mirror of TMT and consists of the world’s largest flat telescope mirror (approximately 3.4m X 2.4 m X 100mm thick) having an elliptical perimeter positioned with an extremely smooth tracking and pointing mechanism in a gravity-varying environment. In order to prepare for developing this unique mirror system, CIOMP has been developing a 1/4 scale, functionally accurate version of the GSSM prototype during the pre-construction phase of GSSM. The prototype will incorporate the same optomechanical system and servo control system as the GSSM. The size of the prototype mirror is 898.5mm×634mm×12.5mm with an elliptical perimeter. The mirror will be supported axially by an 18 point whiffletree and laterally with a 12 point whiffletree. The main objective of the preconstruction phase includes requirement validation and risk reduction for GSSM and to increase confidence that the challenge of developing the GSSM can be met. The precision mechanism system and the optical mirror polishing and testing have made good progress. CIOMP has completed polishing the mirror, the prototype mechanism is nearly assembled, some testing has been performed, and additional testing is being planned and prepared. A dummy mirror is being integrated into the cell assembly prototype to verify the design, analysis and interface and will be used when testing the prototype positioner tilt and rotation motions. The prototype positioner tilt and rotator structures have been assembled and tested to measure each subsystem’s jitter and dynamic motion. The mirror prototype has been polished and tested to verify the polishing specification requirement and the mirror manufacturing process. The complete assembly, integration and verification of the prototype will be soon finished. Final testing will verify the prototype requirements including mounted mirror surface figure accuracy in 5 different orientations; rotation and tilt motion calibration and pointing precision; motion jitter; and internally generated vibrations. CIOMP has scheduled to complete the prototype by the end of July 2016. CIOMP will get the sufficient test results during the pre-construction phase to prepare to enter the preliminary design for GSSM.

Paper Details

Date Published: 27 July 2016
PDF: 15 pages
Proc. SPIE 9906, Ground-based and Airborne Telescopes VI, 99064M (27 July 2016); doi: 10.1117/12.2232068
Show Author Affiliations
Fei Yang, Changchun Institute of Optics, Fine Mechanics and Physics (China)
Hongchao Zhao, Changchun Institute of Optics, Fine Mechanics and Physics (China)
Qichang An, Changchun Institute of Optics, Fine Mechanics and Physics (China)
Peng Guo, Changchun Institute of Optics, Fine Mechanics and Physics (China)
Haibo Jiang, Changchun Institute of Optics, Fine Mechanics and Physics (China)
Linchu Han, Changchun Institute of Optics, Fine Mechanics and Physics (China)
Virginia Ford, Thirty Meter Telescope International Organization (United States)
Glen Cole, Thirty Meter Telescope International Organization (United States)
Byron Smith, XDoubleDout LLC (United States)
Marvin Campbell, MF Campbell Consulting (United States)


Published in SPIE Proceedings Vol. 9906:
Ground-based and Airborne Telescopes VI
Helen J. Hall; Roberto Gilmozzi; Heather K. Marshall, Editor(s)

© SPIE. Terms of Use
Back to Top