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Title: How to calibrate edge sensors on segmented mirror telescopes
Authors: Shelton, Chris
Roberts, Lewis C, Jr.
Keywords: edge sensors
segmented mirrors
Extremely Large Telescopes
capacitive sensor
Issue Date: 3-Jul-2012
Publisher: Pasadena, CA : Jet Propulsion Laboratory, National Aeronautics and Space Administration, 2012.
Citation: SPIE Astronomical Telescopes+Instrumentation, Amsterdam, Netherlands, July 1-6, 2012
Abstract: The next generation of large ground based telescopes use segmented mirrors. Sensors mounted on the edge of the segments measure the relative heights of the segments. The segments are actively controlled in height by three actuators per segment, but lateral motion is only passively constrained. Thus there will be some small change in the gap and shear between segments as changing telescope orientation and temperature make small distortions in the telescope structure. These "in-plane" motions place an additional performance burden on the edge sensors, and on the precision with which they must be mounted relative to the optical surface. In addition, both the scaling and offset of sensor edge height readings also vary with changes in gap.
Appears in Collections:JPL TRS 1992+

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