An illumination mask (10a) for a device for the range-resolved determination of scattered light, having one or more scattered-light measuring structures (11a) which respectively include an inner dark-field zone which defines a minimum scattering range, to an associated image-field mask and a corresponding device is provided. Also provided is an associated operating method and a microlithography projection-exposure system having such a device. The scattered-lighter measuring structure in the illumination mask has a scattered-light marker zone (20a) in the form of a bright-field zone, which on the one hand borders the inner dark-field zone and on the other hand borders an outer dark-field zone, which defines a maximum scattering range. The device may optionally be designed for the multi-channel measuring of scattered light by using a suitable image-field mask and also for multi-channel wavefront measurement, and the detection part may contain an immersion medium. Applications include, for example, the range-resolved determination of scattered light of projection objectives in microlithography projection-exposure systems.