Method and apparatus for determining the position of the target details for the surgical microscope

(57) Abstract: operating microscope, for the determination of the distance between the microscope optical system (8,13) and the target (22), the running time of the light beam reflected by the target out of the microscope (57c) to measure. Transit time is determined by or interference coordination by a phase measurement. Directly in the case of a measurement method for phase measurement, using a modulated light. For interference coordination, partially using coherent light. To achieve high measurement accuracy over a large measurement range, both measurement methods, preferably, in combination used.