Figure 1: PSF shape at the maximum distance from the optical axis (0.71 degrees), at different angles. Contour levels are at 0.05, 0.10, 0.50 of the normalized peak. The scale is in arcsec and each of the four subimages covers 2x2 pixels.

Figure 2: The intrinsic PSF anisotropy (left panel) is greatly reduced when convolved with the seeing (right panel). The right image shows the actual PSF in the best seeing conditions for Paranal (FWHM=0.4 arcsec).