accepts the standard 10 inch reel, 2400 foot IBM reel of tape. 
Necessary control characters can be written on the tape, one 
character at a time, under the control of the operator or the 
computer. 
57. Preparatory Operations: Before actual operation of 
the system is started, there are several functions that must be 
accomplished, After selecting a stereo model and ordering film 
positives at the desired scale and the required density limits 
of .30 to 1.25, the constant data can be prepared, The constants 
to be calculated and entered into the system are: 
a, Effective focal length 
b. Earth curvature 
c. . Air refraction 
IMC 
e. Film shrinkage 
f. Motion constants, if the orientation of the camera 
has changed during exposure (panoramic photography only). 
g. Offset (of principal point) 
h. Lens distortion correction data 
i. Model deformation correction data (This input is 
optional.). 
The constants and corrections must be converted to AP-2 
format for entry into system. 
All of these values except the model deformation function a : 
values, can be calculated using a desk calculator and entered e ) ® 
into the computer, It is not practical to calculate the model 
deformation function manually. In an ideal operation, all of 
the required computer initialization data are prepared automatically 
in a general purpose off-line computer. 
Any exterior orientation information that has been previously 
determined can be entered directly into the computer allowing the 
operator to by-pass that particular phase to which it applies. 
58. General Operational Procedures: All orientation and 
compilation operations of the AS-11B/C system are performed within 
five operating modes: orientation, contouring, profiling, ortho- 
photo, and fill-in. These modes are distinct in that they require 
that different computational and control functions be performed 
by the computer. 
In the initial start-up procedures, which are common to all 
operational modes, the photographs are mounted in the viewer, and 
program and initial-condition tapes corresponding to the camera, 
geometry, and focal-length range are read into the computer. 
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