RK 820 Stereomicroscope with polaroid 
and tv-camera 
% 
Satellite image (orginal 1:400,000) - 
trinned area: 1:50,000, runway 2,750m; 
another trinned area of this, part of 
runway 1,000 m. 
The setting range of the zoom mark is 85 - 570 mm in X-direction 
and 316 mm in Y-direction (without measuring mark). 
By exchanging the front objective lenses you can vary the wor 
king height and thus the observation height of the stereomicros 
cope. However, a convenient observation of the image is guaran 
teed, i.e. first of all you can turn the eyepieces upwards and 
downwards and secondly - as already mentioned - you can 
adjust the head tilt of the eyepiece. Furthermore, the optical axes 
of the eyepieces are slightly tilted outwards to enable a more 
convenient observation. A squint defect correction in the right 
beam path balances a possible eye defect on the part of the 
evaluator. 
After these optical details maybe the most important informa 
tion on the RK 820 for the evaluator: 
■ Of course, the equipment enables an observation in stereo. 
A mono observation is possible both through the left and the 
right zoom arm whereby you can switch by means of the 
single operator button. The "superimposition" is a special 
feature! The effect is that the observator can see the left and the 
right image with both eyes at the same time in the super 
imposition in appropriate deviations. This is a very useful 
option in every case e.g. when the scales slightly deviate from 
each other or when it is difficult to make a stereo adjustment 
of the image pairs. 
The final advantage of the RK 820 is that you can reflect an ad 
ditional variable measuring mark into the right light path. 
Another advantage is the image reversion making work much 
easier especially when processing black-and-white material. 
You do not permanently have to reorient the different grey levels 
since the image is available as a positive. Otherwise, the evalua 
tor must have some experience and the corresponding powers of 
imagination to evaluate and interpret the negative material 
without any difficulty since on the black-and-white negative 
everything is in reverse order. It is often difficult to reorient from 
black-and-white to white-and-black due to the numerous grey 
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