Wind Vibration Analyses of Giant Magellan Telescope
The Giant Magellan Telescope (GMT) will be a 21.5-m equivalent aperture optical-infrared telescope located in Chile. The segmented mirror surface consists of seven 8.4-m diameter mirrors. The telescope structure will be inside a carousel-type enclosure. This paper describes the wind vibration analyses performed on the baseline configuration of the GMT structure during the conceptual design phase. The purposes of the study were to determine order of magnitude pointing and focus errors resulting from the dynamic response of the telescope structure to wind disturbances, and to identify possible changes to the structure to reduce the optical errors. In this study, wind pressure and velocity data recorded at the 8-m Gemini South Telescope were used to estimate the dynamic wind load on the GMT structure. Random response analyses were performed on a finite element model of the telescope structure to determine the structural response to dynamic wind loading and the resulting optical errors. Several areas that significantly contribute to the optical errors were identified using the spectral response curves and the mode shapes. Modifications to these areas were developed and analyzed to determine their effects on the optical performance, and an improved design was developed for the next phase of the design.
SPIE Astronomical Telescopes + Instrumentation