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Durham University

Department of Physics

Staff profile

Publication details for Dr Matthew Townson

Basden, A. G., Bardou, L., Bonaccini-Calia, D., Buey, T., Centrone, M., Chemla, F., Gach, J. L., Gendron, E., Gratadour, D., Guidolin, I., Jenkins, D. R., Marchetti, E., Morris, T. J., Myers, R. M., Osborn, J., Reeves, A. P., Reyes, M., Rousset, G., Stangalini, M., Townson, M. J. & Vidal, F. (2017). On-sky demonstration of matched filters for wavefront measurements using ELT-scale elongated laser guide stars. Monthly Notices of the Royal Astronomical Society 466(4): 5003-5010.

Author(s) from Durham


The performance of adaptive optics systems is partially dependent on the algorithms used within the real-time control system to compute wavefront slope measurements. We demonstrate the use of a matched filter algorithm for the processing of elongated laser guide star (LGS) Shack–Hartmann images, using the CANARY adaptive optics instrument on the 4.2 m William Herschel Telescope and the European Southern Observatory Wendelstein LGS Unit placed 40 m away. This algorithm has been selected for use with the forthcoming Thirty Meter Telescope, but until now had not been demonstrated on-sky. From the results of a first observing run, we show that the use of matched filtering improves our adaptive optics system performance, with increases in on-sky H-band Strehl measured up to about a factor of 1.1 with respect to a conventional centre of gravity approach. We describe the algorithm used, and the methods that we implemented to enable on-sky demonstration.