The diapositives are centered on the picture carriers and the 
reduced focal length is set to 0.G1 mm on the focal length 
micrometers. Each plotting camera has the movements CJ and y> 
The observing microscopes are moved, close and parallel to the 
picture planes on cross-rails, by the space rods. The 7.5x eye 
pieces have a field of view of 22 mm, representing 44 mm in 
the contact print, a feature which has a favourable influence 
on the compilation speed. Coated optics, Dove prisms, adjustable 
eyebase and squint correction by optical wedges are standard 
equipment. 
The space rad intersection is supported by the z column in the 
tracing stand. The platting pencil is forward of the z column; 
the tracing stand therefore has a parallel guide. Control of 
elevation movements is by a drum in the base of the tracing 
stand convenient to the finger tips of the right hand. The 
pencil point is illuminated, can be lifted and has a magnifying 
glass for easy supervision at the further end of the plotting. 
Fig.4. : 
Side table and linear pantograph fitted to the 
B9 for platting at larger scales.