ATP-3-09-02 Field Artillery Survey Download
Page 69 of 168
Angle Determination 16 February 2016 ATP 3-09.02 5-11 Figure 5-15. Vertical angle mean SCALING DISTANCES 5-23. After achieving autoreflection, use the horizontal tangent screw to set the left stadia line on zero on the distance scale of the porro prism (see figure 5-16). If the right stadia line is on the scale, read the number off the scale where the stadia line crosses it. In this example the reading is 8.2 meters. Record the distance in the recorder’s notebook in the Distance column. Figure 5-16. Scaling distance stadia line on scale