Preliminary on-sky results of the CANARY experiment with an ELT-elongated sodium LGS.

We present on-sky results of wavefront sensing on an elongated LGS. These results are derived from observations made with the multi-object AO demonstrator CANARY on the William Herschel Telescope (WHT) in La Palma. The laser guide star is produced using ESO’s transportable Wendelstein LGS unit placed 40 meters away from the WHT so as to replicate the elongations that will be seen on the European ELT. In this analysis, we evaluate the impact of spot truncation and sub-sampling on the wavefront measurements made with the elongated LGS.