I think, if you look real close, the camera is attached to the combing just above the instruments (which slants down to the right) The angled protion of the rod (lens?) sticking out of the camera is probably a prism which projects what is seen in the sight to the camera. The thought has struck me that the camera can (in theory at least) can be mounted anywhere, vertically, horizontally or at about any angle as long as the prism is in the proper position in relation to the gunsight'
The lens for the gun sight is the horizontal circular glass just below the slanted sight glass. It projects the reticle onto the sight glass. The thing that bugs me is, if the camera lens is sticking out into the center of the sight glass, how do you draw a bead?