A 
  
  
  
  
  
  
  
  
  
  
  
   
— 20 — 
b'— excentricity between the rod and the primary axis; 
¢ = excentricity between the short rod and the secondary axis: 
Í — excentricity between the rod and the secondary axis; 
« = angle between the secondary axis and the plane perpendicular to the 
primary axis; 
  
  
  
  
  
  
  
  
  
  
  
  
  
  
n = angle between the short rod and a parallel to the secondary axis; 
Y — angle between the planes parallel to the secondary axis and containing 
the short rod and rod respectively; 
¢ = angle between the rod and a parallel to the secondary axis. 
2 
À 
CE T. e 
I X 
> 
Y 
TT" 
Fig. 14 Geometric diagram of the rod Cardan coupling and of its eccentricities. 
To simplify the diagram, the short rod is placed inside the camera a 
the plate is assumed to be fixed. 
On the basis of the two spacial polygons of both the short rod (5) and the 
rod (B), general formulae were obtained which make it possible to compute 
the influence of these excentricities on the projection of the elements of the 
7’ plane on the z'" plane. 
  
  
  
  
  
    
     
   
   
   
   
  
     
     
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