A system is described for the optical detection of a distant object, having a light beam generating device for generating a parallel light beam, a scanning unit for generating a scan pattern by deflecting the parallel light beam over a defined angular range, and a detector unit for detecting light reflected by the distant object. The scanning unit includes a rotating polygonal mirror with several reflecting partial mirror surfaces. The light beam generating device is provided for generating a parallel light beam in two different beam positions which, in response to a rotating position indicating signal indicating the rotating position of the polygonal mirror, can be switched over from a partial mirror surface to an adjacent partial mirror surface. Accordingly, a system is provided for the optical direction of a distant object, which system has a high capacity. In particular, the system permits the optical detection of distant objects, such as poorly recognizable obstacles, in the air space in the flight direction in front of an aircraft.