Left: image of Fomalhaut on the 256 × 256-pixel CONICA detector. The detector field-of-view is 7′′; i.e., each pixel is 27 mas in size on sky. The ~2.6 arcsec point spread function is due to diffraction of the 78 cm holes in the 9-holes mask used during this observation. The many speckles apparent inside this large Airy pattern are due to the superposition of fringes caused by the 36 spatial frequencies allowed through the mask. Right: power spectrum i.e. squared amplitude of Fourier’s components from the Fomalhaut PSF in the spatial frequency domain.