A method for tracking at least one rigid object part of a rigid reference object, wherein the rigid object part can be detached or removed from the rigid reference object is provided. The method includes obtaining a patient data set of a region around the object part, attaching a first reference star in a fixed position relative to the object part situated on the reference object, detecting reference points on the reference object and ascertaining three-dimensional spatial positions of the reference points of the reference object, assigning the three-dimensional spatial positions of the reference points of the reference object to corresponding points in the patient data set, attaching a second reference star to the object part, ascertaining positional information of the second reference star; and ascertaining positional information of the object part or tracking the object part based on the positional information of the second reference star.