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Proceedings Paper

Fast centroiding with a 24 x 24 frame transfer CCD
Author(s): Hans J. Meyer; Phil J. Kruczkowski; William V. Schempp
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Paper Abstract

A fast centroid processor developed for telescope pointing and high speed tracking is described. It is based on a modified Photometrics CCD camera using a 24 X 24 pixel frame transfer CCD. The small CCD allows very fast update rates (200 frames per second with an 8 X 8 window). It provides good read noise performance (11 e- at 40 kHz read rate) and 16 bit data resolution. A self-adjusting algorithm accomplishes background subtraction. The centroid processor, based on a digital signal processor (Motorola 56001), calculates centroids in real time on 16 bit data to sub-pixel accuracy. The centroid values are converted to 16 bit data words which are used to drive the servos of a chopping secondary mirror on the 2.1 m telescope at Kitt Peak National Observatory. The mirror can track apparent star motion to provide low level (tip/tilt) adaptive correction of astronomical images. A factor of 5 improvement in Strehl ratio is theoretically possible at the 2.1 m telescope with tip/tilt correction. Preliminary results have yielded a factor of 2 Strehl ratio improvement.

Paper Details

Date Published: 12 July 1993
PDF: 6 pages
Proc. SPIE 1900, Charge-Coupled Devices and Solid State Optical Sensors III, (12 July 1993); doi: 10.1117/12.148588
Show Author Affiliations
Hans J. Meyer, Photometrics Ltd. (United States)
Phil J. Kruczkowski, National Optical Astronomy Observatory (United States)
William V. Schempp, Photometrics Ltd. (United States)

Published in SPIE Proceedings Vol. 1900:
Charge-Coupled Devices and Solid State Optical Sensors III
Morley M. Blouke, Editor(s)

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