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On the basis of recent experience, the new model (Fig. 4) was substantially 
improved upon the Jena specimen and its design simplified. Similar to the unit 
described on a previous occasion, the new design permits modifications of the scale 
ratio between the aerial photograph (upper disk) and the template (installed con- 
centrically underneath) from 0.7 to 1.8 times. In addition, it permits to perform 
  
  
  
  
  
Fig. 5. Diagram ot Radial Secator. The large photocarrier disk and the support 
for the templates are presented in phantom view. 
a mechanical , rectification” of photographs taken with tilts up to 20%, if the degree 
and direction of tilt are known. The spotting microscope is readjusted automati- 
cally in accordance with the corresponding angular corrections. For big inclinations 
the length of the punched slots is no longer sufficient to allow for the radial point 
displacements caused by tilt. After the approximate values of these displacements 
have been determined from a table, they are subsequently set on an auxiliary 
scale. It will hardly be economical to perform this transformation automatically. 
Fig. 5 shows the design and manner of operation of the Radial Secator. The large 
photocarrier disk and the template support are presented in phantom view for 
better visibility. A robust angle casting accommodates at its end the basic axis 1—2 
of the unit. The desired radial point of the aerial photograph is optically centred 
on the centre point and mechanical pivotal point 1 of the large disk. This point 
corresponds to the goniometric centre. The template which is perforated in the 
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