First on-sky results of the CAWS wavefront sensor on the CANARY experiment

Nicolas Dubost*, Nazim Bharmal, Maud Langlois, Magali Loupias, Clément Schotte, Michel Tallon, Lazar Staykov, Lisa Bardou, James Osborn, Fanny Chemla, Matthieu Cohen, Tristan Buey, Éric Gendron, Tim Morris

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Citation (Scopus)
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Point-diffraction interferometers are a class of wavefront sensors which can directly measure the phase with great accuracy, regardless of defects such as vortices and disconnected apertures. Due to these properties, they have been suggested in applications such as cophasing of telescope segments, wavefront sensing impervious to the island effect and high-contrast AO and imaging. This paper presents an implementation of this class of interferometer, the Calibration & Alignment~WFS (CAWS), and the results of the first on-sky tests in the visible behind the SCAO loop of the CANARY AO experiment at the William Herschel Telescope. An initial analysis of AO residuals is performed in order to retrieve the SNR of interference fringes and assess the instrument's performance under various observing conditions. Finally, these results are used to test the validity of our models, which would allow for rapid implementation-specific modelling to find minimum-useful flux and other CAWS limits.

Original languageEnglish
Title of host publicationAdaptive Optics Systems VII
EditorsLaura Schreiber, Dirk Schmidt, Elise Vernet
Number of pages15
ISBN (Electronic)9781510636835
Publication statusPublished - 13 Dec 2020
EventAdaptive Optics Systems VII 2020 - Virtual, Online, United States
Duration: 14 Dec 202018 Dec 2020
Conference number: 11448

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


ConferenceAdaptive Optics Systems VII 2020
Country/TerritoryUnited States
CityVirtual, Online
Internet address


  • Adaptive optics
  • Point-diffraction interferometry
  • Wavefront sensing


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