The invention relates to an apparatus (8) for detecting a target position deviation of two bodies (10, 12), with a first measuring unit (14) for placement on the first body (10), a second measuring unit (18) for placement on the second body (12), and an evaluation unit (22). The first measuring unit (14) has means (24) to generate at least one bundle of light beams (28) and a scattering area (34) to scatter light (WV, PV) striking the scattering area, and the second measuring unit (18) has a reflector arrangement (38) to reflect the bundle of light beams (28) onto the scattering area (34). The second measuring unit (18) has a camera (36) to record images of the scattering area (34). The evaluation unit (22) is configured so as to detect from the images a deviation in target position of the bodies (10, 12). The invention additionally relates to a method to detect the deviation in target position.