An improved oblique viewing microscope system including a diffraction grating that oscillates in the plane of the grating and/or an illuminator that oscillates the light rays directed to the object synchronized with the grating period. Additionally, a low frequency diffraction grating is also disclosed. The oscillation and/or low frequency grating provide a high resolution, multi-color image of an object viewed at an oblique angle. A dual oblique viewing microscope system is also disclosed to provide Koehler illumination.