On-Sky Testing of Algorithms for Extended LGS Spots

Alastair Basden*, Andrew P. Reeves, Lisa Bardou, Domenico Bonaccini Calia, Tristan Buey, Mauro Centrone, Fanny Chemla, Philippe Feautrier, Jean Luc Gach, Eric Gendron, Damien Gratadour, David Jenkins, Gianluca Lombardi, Enrico Marchetti, Tim Morris, Richard Myers, James Osborn, Thomas Pfrommer, Marcos Reyes Garcia Talavera, Gerard RoussetEric Stadler, Robert Talbot, Matthew Townson, Fabrice Vidal

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review


We present results of on-sky testing of different algorithms for highly extended LGS spots. We have used the CANARY wide-field AO demonstrator instrument on the 4.2m William Herschel Telescope on La Palma with the ESO Wendelstein LGS unit, launched 40m off-axis to simulate edge sub-apertures of the E-ELT. We investigate the performance of correlation and matched filter algorithms, comparing performance with a traditional centre of gravity. We also present on-sky tests of advanced pixel handling algorithms which we show improve AO system performance, including adaptive windowing (spot tracking), total variation minimisation and brightest pixel selection. Techniques to improve detection of truncated spots are also presented. Additionally, we present a critical study of Shack-Hartmann sensor accuracy with accurate detector readout models, highly applicable to AO system designers when specifying detector performance, or for predicting AO system performance with a given detector.

Original languageEnglish
Title of host publicationAO4ELT5 Proceedings
Number of pages11
Publication statusPublished - 21 Sept 2017
Externally publishedYes
Event5th Adaptive Optics for Extremely Large Telescopes, AO4ELT5 2017 - The Gran Teide Room, Hotel Botánico, Puerto de la Cruz, Tenerife, Canary Islands, Spain
Duration: 25 Jun 201730 Jun 2017


Conference5th Adaptive Optics for Extremely Large Telescopes, AO4ELT5 2017
Abbreviated titleAO4ELT5
CityTenerife, Canary Islands
Internet address

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