There is provided a multi-mirror-system for an illumination system, especially for lithography with wavelengths .ltoreq.193 nm. The system includes light rays traveling along a light oath from an object plane to an image plane, and an arc-shaped field in the image plane, whereby a radial direction in the middle of the arc-shaped field defines a scanning direction. The first mirror and the second mirror are arranged in the light path in such a position and having such a shape, that the edge sharpness of the arc-shaped field in the image plane is smaller than 5 mm in the scanning direction. Furthermore, the light rays are impinging on the first mirror and the second mirror with incidence angles .ltoreq.30.degree. or .gtoreq.60.degree. relative to a surface normal of the first and second mirror.