We comment on the set of visible points of a lattice and its Fourier t
ransform, thus continuing and generalizing previous work by Schroeder
and Mosseri. A closed formula in terms of Dirichlet series is obtained
for the Bragg part of the Fourier transform. We compare this calculat
ion with the outcome of an optical Fourier transform of the visible po
ints of the 2D square lattice.