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Proceedings Paper

Construction and testing of the wavefront sensor camera for the new MMT adaptive optics system
Author(s): Patrick C. McGuire; Troy A. Rhoadarmer; Michael Lloyd-Hart; J. C. Shelton; Michael P. Lesser; James Roger P. Angel; George Z. Angeli; John M. Hughes; Bruce C. Fitz-Patrick; Matthew J. Rademacher; Skip Schaller; Matthew A. Kenworthy; Francois P. Wildi; Jeff G. Capara; David B. Ouellette
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Paper Abstract

This paper describes the construction and testing of the Shack-Hartmann wavefront sensor camera for the new MMT adaptive optics system. Construction and use of the sensor is greatly simplified by having the 12 X 12 lenslet array permanently glued to the detector array, obviating the need for any further realignment. The detector is a frame transfer CCD made by EEV with 80 by 80 pixels, each 24 microns square, and 4 output amplifiers operated simultaneously. 3 by 3 pixel binning is used to create in effect an array of quad-cells, each centered on a spot formed by a lenslet. Centration of the lenslet images is measured to have an accuracy of 1 micrometers rms. The maximum frame rate in the binned mode is 625 Hz, when the rms noise is 4.5-5 electrons. In use at the telescope, the guide star entering the wavefront sensor passes through a 2.4 arcsec squares field stop matched to the quall-cell size, and each lenslet samples a 54 cm square segment of the atmospherically aberrated wavefront to form a guide star image at a plate scale of 60 micrometers /arcsec. Charge diffusion between adjacent detector pixels is small: the signal modulation in 0.7 arcsec seeing is reduced by only 10 percent compared to an ideal quad-cell with perfectly sharp boundaries.

Paper Details

Date Published: 27 September 1999
PDF: 14 pages
Proc. SPIE 3762, Adaptive Optics Systems and Technology, (27 September 1999); doi: 10.1117/12.363583
Show Author Affiliations
Patrick C. McGuire, Steward Observatory/Univ. of Arizona (Spain)
Troy A. Rhoadarmer, Steward Observatory/Univ. of Arizona (United States)
Michael Lloyd-Hart, Steward Observatory/Univ. of Arizona (United States)
J. C. Shelton, Steward Observatory/Univ. of Arizona (United States)
Michael P. Lesser, Steward Observatory/Univ. of Arizona (United States)
James Roger P. Angel, Steward Observatory/Univ. of Arizona (United States)
George Z. Angeli, Steward Observatory/Univ. of Arizona (United States)
John M. Hughes, Steward Observatory/Univ. of Arizona (United States)
Bruce C. Fitz-Patrick, Steward Observatory/Univ. of Arizona (United States)
Matthew J. Rademacher, Steward Observatory/Univ. of Arizona (United States)
Skip Schaller, Steward Observatory/Univ. of Arizona (United States)
Matthew A. Kenworthy, Steward Observatory/Univ. of Arizona (United States)
Francois P. Wildi, Steward Observatory/Univ. of Arizona (United States)
Jeff G. Capara, Steward Observatory/Univ. of Arizona (United States)
David B. Ouellette, Steward Observatory/Univ. of Arizona (United States)


Published in SPIE Proceedings Vol. 3762:
Adaptive Optics Systems and Technology
Robert K. Tyson; Robert Q. Fugate, Editor(s)

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