-25- 
TABLE V 
Orientation Camera azimuth - 20°, set 
ting accuracy - 20 minutes 
Field of View 85° 
V/H Controls 0. 01 to 0. 08 knots per foot; 
- 3% 
A drift reticle (See Figure 10) is provided whose image is super 
imposed on the terrain image. The drift reticle consists of three verti 
cal lines running from top to bottom across the field of view. One line 
passes through the center of the field lens presentation but is discon 
tinuous at a point on the optical axis where a circular bulls-eye indi 
cates Nadir. Two other drift lines are positioned on either side of the 
center line. A scale graduated to + -20° indicates drift. In addition, 
cross lines in the drift reticle indicates the 9x9 inch camera format for 
a six-inch focal length lens. 
If the entire USQ-28 complex is operating, the primary function 
of the photographer’s viewfinder is to monitor the view below for 
adverse weather conditions such as partial cloud cover, fog, adverse 
lighting, etc. If a patch of clouds obscures a part of the flight path, 
the photographer notes this area by marking the start and end of the 
obscured region electronically. When such a section of unacceptable 
photography is "marked" by the photographer, the computer auto 
matically records the location and extent of the unacceptable photog 
raphy whether due to.a cloud cover, equipment malfunction, or pilot 
error. A mission analysis of areas of unacceptable photography is 
accomplished by the computer immediately after landing so that such 
areas can be re-flown on the next mission. In confunction with the 
navigator, the photographer may also note the start and end of such 
unacceptable areas and re-program them for flight later during the 
same mission, if so desired, due to changing cloud cover or other at 
mospheric effects. 
The Point Light Source Figure 11 is used in aximuth measure 
ment by the Sodano or the Flashing Light methods. In the Sodano