AURELIE spot-diagrams on the detector for the typical dispersion configuration : grating 1200 l/mm, order II, ₀ = 6563 Å and ₁ = 6598 Å. Note that the center of images are affected by the central obturation. Physically, the three images inside each dotted rectangle are superposed. The defocusing induced by the image-slicer has been taken into account. The abscissa scales gives the geometrical length in mm from the center of the detector.