Method, device and computer program for measuring an angle between two separated elements and its use

The method involves positioning light detector (6) in second element plane (20) to second element (2). The interference patterns (31,31',31") caused by reference light wave (400') to light detector. The intensity pattern (61,61',61") is formed from the detected diffracted reference light wave. The computer readable data stored angle of incidence (32,32',32") is assigned for the intensity patterns. The angle between the first element plane (10) and the second element plane of the associated angle of incidence is calculated. Independent claims are included for the following: (1) system for measuring angle between two spaced apart elements; and (2) computer program product for measuring angle between two spaced apart elements.