where 1 = lef- 
projector and 2 = right projector 
2. <fyp = the correction to the location of the principal point in the y- 
direction. 
3. dc s the correction to the principal distance. 
4« dt = the correction to the location of the floating mark in the x-direc- 
tion (x-obliquity)• 
5. dl =s the correction to the location of the floating mark in the y-direc- 
tion (width correction) • 
The exterior orientation in A7 and A8 autographs includes the following ele 
ments in each projector: 
A. The location of the nadir point (the foot of the plumb line from the 
projection centre) • 
B • z (the length of the plumb line) • 
C. The angles x 9 <p , co (the rotations around the axes). 
The following notations for the corrections are used: 
1. dx^ = the correction to the location of the nadir point in the x-direction 
2. dy.j = the correction to the location of the nadir point in the y-direction 
3. dz =a the correction to z. 
4* daf=s the correction to X, 
5. dcp ss the correction to <p • 
6. doj= the correction to cj. 
There is a total of 11 elements in each projector, dx^, dy^., and dz are of 
no importance in the adjustment, but by consecutive measurements in both pro 
jectors the base components can be detennined. The following notations for 
the corrections are used: 
1. dbx =s 
2. dby = dy - dy 
W 1 2 
3» dbz = dZp - dz^ in the A7 and d0 = 
dz.. - dZp 
— in the A8 
bx