In most cases refracting and reflecting systems are arranged so that the natural interpupillary distance is reduced.
13 that the objective's exit pupil P'P1' is portrayed by the positive eyepiece, the image P"P i " limits the pencils P ', double microscope; these inverting prisms permit a convenient adaptation of the instrument to the interpupillary distance of the observer.
The cones must be so directed through the divided system that the two exit pupils correspond to the interpupillary distance of the observer.
It can be adapted to the interpupillary distance by changing the tube slide.
The system of Porro prisms employed affords a convenient method of adapting the ends of the eyepieces to the interpupillary distance.
Turning the diaphragms 180° round the optical axis, the orthoscopic impression can be changed into the pseudoscopic. The mechanical arrangement of the eyepiece is such that the distance of the two exit pupils can be adjusted to the interpupillary distance.