A measuring apparatus for determining relative positions of a positioning stage arranged in a moveable fashion in at least one direction by a predeterminable maximum traversing path. The measuring device comprises at least one interferometric measuring means and at least one interferometric correction means. An interferometric measuring means is operable with the laser light of a laser of at least one wavelength. Correction results can be generated with the interferometric correction means allowing conclusions to be drawn with respect to the actual wavelength of the laser light during a position determination of the positioning stage in order to take into account variations of the wavelength of the laser light, in particular due to ambient conditions, when evaluating the measuring results. The interferometric correction means is arranged proximate to the interferometric measuring means, and the proximity corresponds to a predeterminable portion of the maximum traversing path of the positioning stage.