INO Pyramidal Wavefront Sensor Demonstrator: first closed-loop on-sky operation at Mont-Mégantic Telescope

Wavefront sensing is one of the key elements of an Adaptive Optics System. As an alternative to the commonlyencountered, commercially available Shack-Hartmann WFS (SH-WFS), the more recent Pyramid-WFS (P-WFS) isproving to be a very attractive technology, thanks to its high-sensitivity and robustness against aliasing. At INO, centerfor applied research in optics and technology transfer in Quebec City, Canada, we have developed a compact andflexible P-WFS prototype that can be integrated into an AO system. This P-WFS prototype includes a fast piezo-electricmodulation mirror and a high-sensitivity EMCCD camera. Our P-WFS was installed on the experimental AO systemdeveloped by Laval University in Quebec for the 1.6-m Mont-Megantic telescope, which also includes a commercialhigh-speed SH-WFS. The architecture is such that both WFSs can take measurements simultaneously, and either one canbe used to drive the deformable mirror. Here we present the on-sky results obtained with the INO P-WFS module.