Sign on

SAO/NASA ADS Astronomy Abstract Service

· Find Similar Abstracts (with default settings below)
· Electronic On-line Article (HTML)
· Table of Contents
· Also-Read Articles (Reads History)
·
· Translate This Page
Title:
Cornell Caltech Atacama Telescope primary mirror surface sensing and controllability
Authors:
MacDonald, Daniel; Woody, David; Bradford, C. Matt; Chamberlin, Richard; Dragovan, Mark; Goldsmith, Paul; Radford, Simon; Sebring, Thomas; Zmuidzinas, Jonas
Affiliation:
AA(Jet Propulsion Lab. (United States)), AB(California Institute of Technology (United States)), AC(Jet Propulsion Lab. (United States)), AD(California Institute of Technology (United States)), AE(Jet Propulsion Lab. (United States)), AF(Jet Propulsion Lab. (United States)), AG(California Institute of Technology (United States)), AH(Cornell Univ. (United States)), AI(Jet Propulsion Lab. (United States))
Publication:
Ground-based and Airborne Telescopes II. Edited by Stepp, Larry M.; Gilmozzi, Roberto. Proceedings of the SPIE, Volume 7012, pp. 701211-701211-9 (2008). (SPIE Homepage)
Publication Date:
08/2008
Origin:
SPIE
DOI:
10.1117/12.790528
Bibliographic Code:
2008SPIE.7012E..35M

Abstract

To meet the 10 µm RMS half wavefront error requirement for the 25 m diameter Cornell Caltech Atacama Telescope (CCAT), active control of the approximately 200 primary mirror panels is required. The CCAT baseline design includes carbon fiber aluminum honeycomb sandwich mirror panels. Distortions of the panels due to thermal gradients, gravity and the mounting scheme need to be taken into consideration in the control system design. We have modeled the primary mirror surface as both flat and curved surfaces and have investigated mirror controllability with a variety of sensor types and positions. To study different mirror segmentation schemes and find acceptable sensor configurations, we have created a software package that supports multiple segment shapes and reconfigurable panel sizing and orientation. It includes extensible sensor types and flexible positioning. Inclusion of panel and truss deformations allows modeling the effects of thermal and gravity distortions on mirror controllability. Flat mirrors and curved mirrors with the correct prescription give similar results for controlled modes, but show significant differences in the unsensed flat mirror modes. Both flat and curved mirror models show that sensing schemes that work well with rigid, thermally stable panels will not control a mirror with deformable panels. Sensors external to the mirror surface such as absolute distance measurement systems or Shack-Hartmann type sensors are required to deal with panel deformations. Using a combination of segment based sensors and external sensors we have created a promising prototype control system for the CCAT telescope.
Bibtex entry for this abstract   Preferred format for this abstract (see Preferences)
   

Find Similar Abstracts:

Use: Authors
Title
Abstract Text
Return: Query Results Return    items starting with number
Query Form
Database: Astronomy
Physics
arXiv e-prints