Control challenges for extremely large telescopes

Douglas G. MacMartin

doi:10.1117/12.484661

14 August 2003 Control challenges for extremely large telescopes

Douglas G. MacMartin

Proceedings Volume 5054, Smart Structures and Materials 2003: Industrial and Commercial Applications of Smart Structures Technologies; (2003) https://doi.org/10.1117/12.484661
Event: Smart Structures and Materials, 2003, San Diego, California, United States

Abstract

The next generation of large ground-based optical telescopes are likely to involve a highly segmented primary mirror that must be controlled in the presence of wind and other disturbances, resulting in a new set of challenges for control. The current design concept for the California Extremely Large Telescope (CELT) includes 1080 segments in the primary mirror, with the out-of-plane degrees of freedom actively controlled. In addition to the 3240 primary mirror actuators,the secondary mirror of the telescope will also require at least 5 degree of freedom control. The bandwidth of both control systems will be limited by coupling to structural modes. I discuss three control issues for extremely large telescopes in the context of the CELT design, describing both the status and remaining challenges. First, with many actuators and sensors, the cost and reliability of the control hardware is critical; the hardware requirements and current actuator design are discussed. Second, wind buffeting due to turbulence inside the telescope enclosure is likely to drive the control bandwidth higher, and hence limitations resulting from control-structure-interaction must be understood. Finally, the impact on the control architecture is briefly discussed.

Citation Download Citation

Douglas G. MacMartin "Control challenges for extremely large telescopes", Proc. SPIE 5054, Smart Structures and Materials 2003: Industrial and Commercial Applications of Smart Structures Technologies, (14 August 2003); https://doi.org/10.1117/12.484661

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