deviation 
rricrons 
Fig. 2. 4:1. Deviations between the radial dis 
tortion effects of four correction 
glass plates and the distortion to 
be compensated. 
dr'microns 
Fig. 2. 4;2. Deviations between the radial distortion effects 
of two correction glass plates and the distortion 
to be compensated. The radial distortion inclu 
des atmospheric refraction and curvature of earth, 
flying altitude 4500 m. 
Adr' mtcrors 
Fig. 2.4:3. Deviations between the radial distortion 
effects of four projector correction glass 
plates and the avera-ge«ffistortion to be 
compensated.