Abstract: A night-vision instrument for presenting a 1:1 image comprises an objective, an image intensifier or converter tube, an ocular, a flat double-sided input mirror, and an optical system adapted to transfer the image appearing on the phosphor screen of the intensifier to the ocular. The ocular axis is in line with the viewed object, while the objective and the intensifier have their axis positioned at a right angle to the viewing axis. The input mirror is positioned in front of the ocular inclined at 45.degree. to its axis and to the axis of the objective, so as to direct the light rays received from the viewed object through the objective onto the cathode of the intensifier. The intensified image appearing on the phosphor screen is directed to the rear side of the input mirror by one single prism, one inclined mirror, one double prism and an optical lens system. The rear side of the input mirror projects the image through the ocular into the eye of the observer.