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5. The image quality should be equal to that of the wellknown Aviogon lens. 
6. The lens should be free of diaphragm differences. 
7. A similar super-wide-angle lens should be made available for infrared photography. 
L. Bertele developed in the course of protracted investigations an optical system fully 
meeting the enumerated requirements. The new super-wide-angle lens, the ''Super- 
Aviogon" and the corresponding ''Super-Infragon" for infrared photography, have the 
foeal length f — 88 mm (approx. 31/,”) and a theoretical maximum distortion of only 
Æ 5 microns. They are further developments of the Aviogon lens (fig. 2). 
The WILD RC9 Camera. 
The very wide angular field of the new lenses made it necessary to construct a 
camera in which the cone is mounted at such depth that the floor opening of the aircraft 
does not interfere by cutting off a part of the produced picture. 
Plotting Equipment for Aerotriangulation and Mapping from Photographs 
taken with a Super-Wide-Angle Lens. 
The combination of the Stereocomparator with an electric coordinate Printer for 
analytical aerotriangulations and comparatively simple plotting machines is reserved for 
such cases in which programme controlled computing automats are available. On the other 
hand, it is mostly preferable to use an Autograph for systematic small scale cartography, 
as this instrument allows both aerotriangulation by spatial extension of control and 
detail plotting. The present autographs are, however, not suitable for plotting super-wide- 
angle photographs for the reason that the operation range of the space-rods is too small. 
The construction of a new Autograph proved necessary. 
For the selection of the plotting principle the necessary orthogonal observation of 
the pictures was decisive. For the correct interpretation of the character of the terrain 
and the course of the contour lines also in the corners of the model, the movement of the 
floating mark from the centre to the borders of the optical threedimensional model 
must not be tilted to the horizontal plane. Furthermore, the observer should not have an 
oblique view of the model, as it is the case for various types of double projectors. The 
orthogonal observation has the advantage to supply the impression that the contour lines 
of the model always lie parallel to the stationary horizontal picture plane. The operator 
is therefore never in doubt, even for difficult terrain, how the contour line actually runs, 
and this both in plotting the middle of the mode! and the border parts. The mechanical 
plotting principle, in which the projection rays are represented by space-rods, is disting- 
uished by the property of orthogonal observation for the whole model, and for such 
reason the approved mechanical plotting principle was retained. 
For permitting the shortest and lightest possible construction of the space-rods and 
to hold the machine in reasonable dimensions notwithstanding the large tilt of the space- 
rods, it was found necessary to reduce the pictures taken with the aerial camera to the 
half size in a reduction printer. The transformation of the pictures can be combined 
with a compensation of the residual distortion. For comparatively flat terrain it is even 
possible to eliminate the influence of the curvature of earth and refraction by special 
optical correction plates which are computed for given flight altitude ranges. In such 
case the height above sea level can be read correctly on the height counter during plot- 
ting. For larger height differences this method is of course not precise, but the inaccur- 
acies do not exceed the tolerance of small-scale maps. The compensation for a fligt height 
of 6000 m (20,000 ft.), would only show an error of about 1 m (3.3 ft.) per 1000 m 
(3,300 ft.) height difference. 
The special plotting equipment for super-wide-angle photographs is the WILD A9 
Autograph which contains various constructional elements that have proved their merits 
in the WILD A7 and A8 Autographs.