54 BALLISTIC PHOTOGRAMMETRY, DISCUSSION 
known to be accurate to at least = 2 y. 
It must be concluded therefore, that bias 
errors exist which are covered up due to sym- 
metrical nature of the distortion pattern. Thus, 
a second type of evaluation was performed as 
first evaluation. Figure 7 shows that the tan- 
gential distortion over most of the lens cone is 
within the — 2 micron limit of the measuring 
accuracy. However, there are areas where 
variations in tangential distortion up to 8 
lt! 
Fig. 5. Radial and Tangential Distortion. Astrotar BC-4. No. 265. 
indicated in the lower right hand side of Figure 
3. The corresponding result is graphically pre- 
sented in Figures 5, 6, and 7. Figure 6 demon- 
strates clearly that the radial distortion, in this 
case, is expressed much better by an elliptical 
pattern, as shown by the somewhat irregular 
heavy lines in contrast to the thin lines repres- 
enting the radial distortion obtained from the 
microns occur between rather adjacent points. 
Such local disturbances are objectionable espe- 
cially if the photogrammetric method is used 
to record a sequence of individual points as 
eg a flashing satellite, thus depending entirely 
on the possibility of reconstructing precisely, 
for the purpose of triangulation, the spatial 
configuration of individual rays. 
Discussion 
Herr Prof BURKHARDT: Ich danke Herrn Dr 
Schmid fiir seinen sehr aufschlussreichen Vor- 
trag. Ich glaube, es sind eine Menge von Pro- 
blemen angeriihrt, die uns auch in unseren 
anderen Arbeiten ausserordentlich interessie- 
ren. Ich darf zunächst Herrn Rosenfield bitten, 
die Dis 
Ausseru 
Schmid: 
Mr ( 
to his p 
Optical 
Camera 
Mr 
about 
that you 
tenths 
What i 
standar 
thinkin; 
Mr 
measur 
error of