Slit viewer (SV) camera image of fibers reimaged by the FEM. The cross-like diffraction pattern, particularly visible for the AO guide fiber, is induced by a pupil mask installed on the MACAO DM for calibrations. The image is done with a closed loop on MACAO and by offsetting the center of the guide window on the SV camera so that the science and reference fibers are moved out of the slit (dashed vertical lines).