An optical rotary encoder, comprising an encoder disc, comprising: at least one measuring track designed such that when a scanning area of the measuring track is illuminated, at least one optical measuring beam is generated, wherein at least one optical parameter of the measuring beam is modulated as a function of the angle to be measured, and wherein the measuring track is arranged in a first radial area of the encoder disc; and at least one compensating track arranged in a centered manner with respect to the measuring track on a second radial area of the encoder disc, wherein the center of the measuring track coincides with the center of the compensating track; an optical or optoelectronic scanning device designed to illuminate a scanning zone of the measuring track of the encoder disc, comprising: an illumination device designed to illuminate an area of the compensating track of the encoder disc with light, wherein at least beam is generated; a deflecting device (30; 32, 34) designed and arranged to deflect the beam generated by illumination of the compensating track onto the scanning area of the measuring track, wherein the scanning area of the measuring track is illuminated by the deflected beam, the optical rotary encoder being characterized in that: the beam generated by illumination of the compensating track is directed radially in the direction of the axis through the common center of the compensating and measuring tracks (22, 24). at least one measuring track designed such that when a scanning area of the measuring track is illuminated, at least one optical measuring beam is generated, wherein at least one optical parameter of the measuring beam is modulated as a function of the angle to be measured, and wherein the measuring track is arranged in a first radial area of the encoder disc; and at least one compensating track arranged in a centered manner with respect to the measuring track on a second radial area of the encoder disc, wherein the center of the measuring track coincides with the center of the compensating track; an optical or optoelectronic scanning device designed to illuminate a scanning zone of the measuring track of the encoder disc, comprising: an illumination device designed to illuminate an area of the compensating track of the encoder disc with light, wherein at least beam is generated; a deflecting device (30; 32, 34) designed and arranged to deflect the beam generated by illumination of the compensating track onto the scanning area of the measuring track, wherein the scanning area of the measuring track is illuminated by the deflected beam, the optical rotary encoder being characterized in that: the beam generated by illumination of the compensating track is directed radially in the direction of the axis through the common center of the compensating and measuring tracks (22, 24). an illumination device designed to illuminate an area of the compensating track of the encoder disc with light, wherein at least beam is generated; a deflecting device (30; 32, 34) designed and arranged to deflect the beam generated by illumination of the compensating track onto the scanning area of the measuring track, wherein the scanning area of the measuring track is illuminated by the deflected beam, the optical rotary encoder being characterized in that: the beam generated by illumination of the compensating track is directed radially in the direction of the axis through the common center of the compensating and measuring tracks (22, 24). the beam generated by illumination of the compensating track is directed radially in the direction of the axis through the common center of the compensating and measuring tracks (22, 24).