Diffraction images of incoherent disk objects formed by a polarizing microscope with crossed polarizers are studied. Expressions for intensity distribution have been derived and the results in the form of curves have been plotted. Results are also applicable to the performance of the system in partially space coherent illumination with besinc form of coherence function. The images, which are of unusual shape, different from the Airy-type patterns formed by the ordinary microscope, are strongly dependent upon the size of the disk/coherence parameter.