Optical Plummet - David White DT8-05P Owner's Manual

Circular Leveling Vial
If the circular vial is centered after leveling
the plate vial, then no further adjustment
is necessary. If not, proceed with the
following adjustment.
A. Using the adjusting pin, provided in
the case, turn the adjusting screws
until the bubble is centered in the vial.
Do not over tighten the adjusting screws
B. Loosen one screw by turning it 1/4
turn, then tighten the other screw by
1/4 turn.

Optical Plummet

This adjustment is required to make
the line of sight of the optical plummet
coincide with the vertical axis.
A. Point the optical plummet at a ground
target. This can be done by adjusting
the level screws or by loosening
the instrument fastening screw and
moving the instrument over the
target.
B. Turn the instrument 180° and
re-sight the target through the optical
plummet. If the target is still centered,
no adjustment is necessary. If not, go
to next step.
D. Using the adjusting pin, provided in
the case, turn the reticle adjusting
screws until half the displacement has
been removed. Loosen one screw
1/4 turn, then tighten the opposing
screw 1/4 turn.
E. Repeat steps A through D until there
is no displacement of the target when
the instrument is turned about its
vertical axis.
Collimation Error
• Attach the instrument on a tripod and
precisely level.
• Aim at point A in the distance with the
normal, direct position of telescope.
Record the reading of the horizontal
angle - HR-DIRECT.
• Using the reverse position of the
telescope, take the reading of the
A
horizontal angle - HR-REVERSE, then:
Collimation Error C = (HR-Direct -—
HR-Reverse ± 180°)/2
A
If C <10", no adjustment is required.
A´
If C >10", the following adjustment is
required:
• Adjust the horizontal fine motion in
the reverse position of the telescope
so that the reverse reading HR-Rev =
HR-Rev + C.
• Remove the protective cover of the
reticule of the telescope and adjust
both the left and right adjusting
screws so that the vertical hair of the
reticule coincides with object A.
• Repeat the steps until acceptable
condition is reached.
-16-
Ground
Target
Stadia
Hairs
L
B
A ´
half the
distance