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28 June 2006 Lick Observatory adaptive optics wavefront sensor upgrades
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The wavefront sensor camera and tip/tilt sensor APDs that were on Lick Observatory's Shane 3 Meter Adaptive Optics system were over a decade old and showing their age. They were recently upgraded. The first upgrade was to convert from quad-APDs in the laser guidestar mode natural star tip-tilt sensor to a sensitive low-noise CCD. The new CCD in this position, an 80x80 E2V CCD-39 inside a SciMeasure camera, has a low enough read noise, ~3 e-/pixel, that the tip/tilt measurement in closed-loop operation is photon noise limited and thus benefits from the improved quantum efficiency of the CCD. We have demonstrated on-sky up to two magnitudes of improvement in viable tip/tilt star brightness, which greatly extends the available sky coverage in the laser guidestar AO mode. Also, the increased field of view of the new tip/tilt sensor provides a much more reliable means of acquiring and locking on dim tip/tilt stars, making the whole system operationally more efficient. In the second phase of the upgrade project, the high order wavefront sensor has been replaced, also with a CCD-39 chip in a SciMeasure camera. In this paper we will describe these upgrades and present preliminary performance results.
© (2006) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
David Palmer, Donald Gavel, and Elinor Gates "Lick Observatory adaptive optics wavefront sensor upgrades", Proc. SPIE 6272, Advances in Adaptive Optics II, 62721D (28 June 2006);

Cited by 1 scholarly publication.

Adaptive optics



Avalanche photodetectors

CCD cameras

Wavefront sensors


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