Hello friends
There are very interesting details I can read here! Thank you all.
To the last question from Vlad: Well, I don't know the definition about the difference between a larg telephoto lens and a telescope, but I think we can talk about a telephoto lens in this case. In our days we can find things like this:
The Zeiss Apo Sonnar T* 1700mm/4, a monster device with 256kg ...
http://www.dpreview.com/news/0610/06100101zeiss1700f4.aspLuis, you are probably right with the optical path you have drawn. And I'm also thinking that the reflex mechanism is an additional one outside the camera body. The reason for this may be the need for a better viewfinder with the decomposer prism.
For the auto focus ... I can't see any evidence for such a function in the drawing. It would make no sense to me to have such a complicated optical system in the region of the viewfinder for the AF-sensor. It could be mounted just above the decomposer prism.
My guess for the double viewfinder is, that one shows the total of the picture and the other is a focusing aid with strong magnifier.
I can't see also any motor on the drawing. Okay, this little device near the reflex mirror could be one, but I think this could also be an electric magnet for moving the mirror.
There are also two rotary knobs (see 42-45) maybe for manually adjusting the focus (but don't ask me why there are two knobs needed for this ...).
Best wishes - Guido