The projection lenses (f = 110mm 1 : 16) have six components. The 
condensers are advanced fresnel lenses, the lamps iodide 250 W, cooled by 
blowers. The quality of the image may thus be as good as that of an instrument 
with paraxial optics. 
2 The F-2 Planitop, Carl Zeiss Oberkochen 
(ref Schwebel, R ., The F-2 Planitop Topographic Plotter 
Bul, special English Edition, 1974). 
The principal aims of the instrument are the production and revision 
of topographic maps. As such it seems to be the successor of the Stereotop, the 
"approximate" instrument. It is a very small instrument, the required floor 
space, even with external pantograph, is only 2.7 m? (without it, 0.7 m?! ). The 
instrument has not much in common with its elder brothers the Planimat and 
the Planicart. What it does have in common is that the photographs move for 
tracking. The space rods are of the two-arm type. The rotation axes for w 
are not excentric; the 0 -axes are excentric, but, unlike the other two instru- 
ments, in the X-direction. This necessitates a (small) over-correction of q in 
relative orientation. 
To reach the larger map : model ratios mentioned in the table, the 
external tracing table should be attached. The pantograph is of the same type 
as is used for the B8 and PG2. 
3 The Stereosimplex G6, Galileo Santoni 
This newest plotter of Galileo, for small and medium scale, has some 
properties in common with the Stereosimplex IIC. It was the designer's aim to 
produce an instrument that could be manufactured at costs comparable with 
the topographic plotters on the market. He has certainly succeeded in this, and 
it is really one of the lowest priced of photogrammetric instruments. In the 
table the instrument is compared with some of its competitors. Here we com- 
pare it with its more expensive counterpart, the Simplex IIC. It differs in that 
the mechanical photo-planes are situated between perspective centres and 
model, as with the B8, the Planicart, and the Planimat. The principal distance 
is set on one screw for each projector only, which makes it simpler for the 
operator (the Simplex IIC has three screws, two of which are turned with one 
key). The distortion compensation is by means of the usual Santoni cams.