The lower accuracy in oj can be explained again by the fact that the B-8 has an 
instability in the co direction of approximately ^"2^, which influences the 
determination of the values for absolute CO in the plotter. 
Fig. 20 - Aerial Photograph taken in Nigeria with a 
Wild RC-9 Camera Equipped with Super-Infragon 
Lens and using Infra-Red Film 
In addition, we.also evaluated the accuracy of tip and tilt 
determined by comparing horizon pictures of adjacent flight lines and using only 
one ground-controlled stereo model in the block. Horizon pictures of different 
flight lines flown on the same day were measured in the stereo microscope using 
a single reference picture for the entire block. For example, if Line 1 were 
flown north, and Line 2, south, then the forward horizon photographs of Line 1 
would be compared with a reference aft horizon photograph of Line 2 for the 
determination of differential . We chose picture 52 of Line 3 as the 
reference picture and determined ^ for the ground-controlled aerial photographs 
in Lines 1, 2, 4, 5, 7, and 8. The results are as follows: