Pentax AP-120 Gebrauchsanleitung Seite 6

certain that the compensator is working. Turn the foot screws again
until the bubble moves back to the center. If the relative position
between the target image and the horizontal reticle line has not
changed, the compensator operation is good. It's important to check
the compensator before using the instrument.
4.3. Sighting and focussing
Look into the aiming sight and turning the instrument by hand. Point
the telescope roughly at the leveling staff. Turn the focussing knob
until the staff image appears sharp and free from parallax with
respect to the reticle. Bring the vertical reticle line exactly on to the
center of the staff by turning the horizontal drive screw..
4.4. Operations
4.4.1. Determining the difference in elevation
➀
Set up and level the instrument about halfway between two
points, say A and B (see Fig. 2).
a
➁
Set staff on point A and B. Note the reading a on A, then the
reading b on B by using the instrument.
➂
The difference in elevation of A, B is H=a-b
4.4.2. Stadia surveying (See Fig. 3).
1/2
A
s
b
B
h
1/2
A1 1.643m
A2 1.124m
Fig. 3
Fig. 2
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