In some embodiments, the disclosure provides a system that includes an optical element group including a plurality of optical elements configured to project a pattern of an object in an object plane to an image plane. The system also includes a unit configured to detect an image selected from an image of at least part of the projection the pattern of the object, and an image of a measurement element arranged in the area of the object. The image is created via at least some of the optical elements in the optical element group. The unit is configured to determine an imaging error in the projection of the pattern of the object from the object plane to the image plane. The device is configured to be used in microlithography.