The Rbl. Flak is used with heavy antiaircraft guns for indirect fire against ground targets and for reciprocal laying. A modified type is designed for use with the predictor.
When mounted in their respective sockets with the azimuth scales set to zero, the line of sight of the panoramic telescope on the predictor is 180° from that of the predictor telescope. The reason for the eyepiece of the gun sight being 90° from the axis of the gun is for convenience as the operator can stand at the right side of the gun and look into the sight at right angles to the axis of the gun. This sight is 9.3 inches in height.
German: p. 185 (August 1, 1945)