Abstract: In a method for correcting optical wavefront errors in an optical system, the optical wavefront is calculated for different wavelengths and fields of view between the entry pupil (EP) and exit pupil (AP). Any phase differences are compensated by at least one surface (5, 7) compensating the phase differences in the beam path. A particular optical system, expediently in the form of a telescope, accordingly has a beam path which comprises the following: a first reflector (3), arranged along its axis (A), for reflecting a beam (1) incident along an optical axis (O) onto a concave second reflector (4) which throws the beam obtained from the first reflector (3) onto a third reflector (5), from which it is passed to a concave fourth reflector (6) in order to be reflected at an angle with said optical axis (O). Such a means (5, 7) for correcting the wavefront errors is provided in the beam path of such an optical system.

Abstract: A process is disclosed for correcting wave front deformations caused by an optical system (5). The wave front deformations are measured by means of a wave front measurement instrument. Based on the measurement results, at least two optical components are selected as optical correcting elements (1, 2) from a series of prefabricated optical components, for example cylindrical, with form errors of different types and magnitudes. They are then mutually aligned and brought into the path of the rays of the optical system (5). This process meets high tolerance requirements an may be easily and quickly applied in the course of manufacture of an optical system (5).