(a) Elevation normal to principal plane
FIGURE 31
Then *j = +40.63 cos 18° - 73.72 sin 18° - +15.86 mm; y« = - (+40.63) sin 18° +
(-73.72) cos 18° + 153.6 tan 2°54' = -74.89 mm. Similarly, x'b = -78.74 cos 18° + 20.32
sin 18° = -68.61 mm; ^ = - (-78.74) sin 18° + 20.32 cos 18° + 153.6 tan 2°54' = + 51.44
mm.
- Write the equations of the datum-plane coordinates
Let X and Y denote coordinate axes that lie in the datum plane and in the same vertical
planes as the x' and y' axes, respectively, as shown in Fig. 31. Draw the horizontal line kq
Datum plane
Ground
Horizontal
Optical axis
Vertical
