The invention concerns a projection objective of a microlithographic projection exposure apparatus designed for EUV, for imaging an object plane illuminated in operation of the projection exposure apparatus into an image plane. The projection objective has at least one mirror segment arrangement comprising a plurality of separate mirror segments. Associated with the mirror segments of the same mirror segment arrangement are partial beam paths which are different from each other and which respectively provide for imaging of the object plane (OP) into the image plane (IP). The partial beam paths are superposed in the image plane (IP). At least two partial beams which are superposed in the same point in the image plane (IP) were reflected by different mirror segments of the same mirror segment arrangement.