A method for aligning an optical measuring system comprises the provision of an optical measuring system having the following as optical elements: a beam splitter; a first photo sensor, on which a first sub-beam from the beam splitter impinges; an optical filter; and a second photo sensor lying behind the optical filter in the beam direction, a second sub-beam from the beam splitter impinging on said sensor. The angular position and relative position of a number of the optical elements to one another can be aligned. The method further relates to: the provision of a device for forming a differential signal from the signals of the two photo sensors; the provision of a light source having a polarisation that modifies over time and the irradiation of light into the beam splitter such that a single sub-beam impinges on each photo sensor; the formation of a differential signal from the output signals of the photo sensors; the variation of the position and/or angular position of at least one of the optical elements and the monitoring of the differential signal; the determination of the angular positions/ position of said elements in which the differential signal has a minimum value and the setting of the angular positions of the optical elements according to the determined values. The invention also relates to a corresponding system.