FIELD: measurement technology. SUBSTANCE: device has laser, condenser, optical diaphragm, semitransparent mirror, collimating objective, illuminator, autocollimation mirror, mirror, receiving unit objective, focusing screen, photocondenser, objective reducing the maximum period of inhomogeneities under examination to 1 mm and adjusting Schmidt phase plate. The frontal focal plane of the objective is coincident with that of the receiving unit objective having focal length f=489.2 mm. The adjusting Schmidt phase plate is placed in front of the receiving unit objective which profile α(x)(x) satisfies an equation α(x)=do+7,5·10-5x4-6,5·10-6x6, where do is the thickness of the correcting Schmidt phase plate. The focusing screen is 1000 mm distant from the receiving unit objective. EFFECT: improved quality of visual image. 6 dwg
