Average VISIR images of the PSF calibrator Aldebaran (left image of each column) and Betelgeuse (right image of each column) in 8 filters from 7.76 to 11.25 μm (left column) and 11.85 to 19.50 μm (right column). The color scale is a function of the square root of the intensity, scaled to the minimum and maximum values in each image. The field of view is 5.63″ × 5.63″ for all images, with North up and East to the left. The images of Aldebaran in the PAH1, SIV and PAH2 filters, as well as all the N band images of Betelgeuse include a correction of the PSF core saturation (see Sect. 2.3 for details).