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Proceedings Paper

Innovations within the Altair real-time wavefront reconstructor
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Paper Abstract

The Gemini North adaptive optics system Altair utilises five cooperative CPU's to perform all the associated real-time tasks. One, the reconstructor (RTC), manages all of the highest speed hard real-time duties. As well as the core, computationally intensive, wavefront reconstruction, this processor implements a number of algorithms providing control system support services. These include: the quad-cell centroid gain estimation, determination and subtraction of invisible modes on the deformable mirror, and the blending of tip, tilt and focus from the on instrument wavefront sensors (which exist on all facility Gemini instruments). These associated support tasks are critically important to ensure that the system always runs with an optimal bandwidth and produce stable images with no artefacts such as a waffle pattern or residual non-common path errors. We present the original algorithm that we have developed for the centroid gain estimate and discuss how it is efficiently and conveniently implemented on the hard real-time processor.

Paper Details

Date Published: 25 October 2004
PDF: 9 pages
Proc. SPIE 5490, Advancements in Adaptive Optics, (25 October 2004);
Show Author Affiliations
Leslie K. Saddlemyer, Herzberg Institute of Astrophysics, NRC (Canada)
Glen Herriot, Herzberg Institute of Astrophysics, NRC (Canada)
Jean-Pierre Vrran, Herzberg Institute of Astrophysics, NRC (Canada)
Malcolm Smith, Herzberg Institute of Astrophysics, NRC (Canada)
Jennifer Dunn, Herzberg Institute of Astrophysics, NRC (Canada)

Published in SPIE Proceedings Vol. 5490:
Advancements in Adaptive Optics
Domenico Bonaccini Calia; Brent L. Ellerbroek; Roberto Ragazzoni, Editor(s)

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