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Measurement accuracy in control of segmented-mirror telescopes
Douglas G MacMartin1, Gary Chanan
1Department of Control and Dynamical Systems, California Institute of Technology, Pasadena, California 91125, USA. macmardg@cds.caltech.edu
Applied Optics
|February 10, 2004
Summary
Future large optical telescopes with segmented mirrors can rely on mechanical sensors for precise control. Sensor noise from mechanical sensors will not degrade observations, making supplemental wave-front sensors unnecessary for real-time figure control.
Area of Science:
- Astronomy and Astrophysics
- Optical Engineering
- Telescope Technology
Background:
- Future large optical telescopes feature segmented primary mirrors requiring active control of segment positions.
- Accurate control of these segments is crucial for optimal telescope performance.
Purpose of the Study:
- To estimate the impact of sensor noise on primary mirror control accuracy in future large optical telescopes.
- To compare the precision of mechanical sensors versus optical wave-front information for segment control.
Main Methods:
- Utilizing data from the Keck telescopes to derive realistic noise estimates for mechanical sensors.
- Comparing the accuracy of mechanical segment motion measurements with optical wave-front data.
Main Results:
- Mechanical sensors provide more accurate measurements than optical wave-front information for current telescope designs.
- Sensor noise from mechanical sensors is unlikely to significantly degrade seeing-limited or diffraction-limited observations.
Conclusions:
- Mechanical sensors are sufficient for real-time figure control of future large optical telescopes.
- Supplemental wave-front sensors are not required, simplifying telescope design and operation.
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