Among other items, an illumination device (110) is [provided] for an observation device (100) having one, two or more observation beam paths, each with at least one observation beam bundle, in particular for an operating microscope, having at least one light source (112) for producing at least one illumination beam path with at least one illumination beam bundle (121, 122, 123) for illuminating an object to be observed, in particular, an eye to be observed, in addition having at least one illumination optics unit (11)*, which is constructed according to the Köhler principle of illumination, as well as an objective element (119), wherein the at least one illumination beam path or the at least one illumination beam bundle (121, 122, 123) runs coaxially to an observation beam path or observation beam bundle. In order to produce an optimal solution to the problem of practical requirements relative to homogeneity of the red reflex with a simultaneous good contrasting of the lens pieces or membranes in the lens capsule, it is provided that an intermediate image (125) of the light source (112) lies in the front focal point of the objective element (119), viewed in the direction of the light, or that an intermediate image (125a) of the light source (112) lies at a distance from the front focal point of the objective element (119) corresponding to a maximum of 50% of the focal length of the objective element (119), viewed in the direction of the light. *sic: (111)?—Trans. Note.
