CST/BERGER Theodolite DGT 10 Manual Original página 22

measuring tool until the measuring point on the ground is
centred in the optical plummet.
Tighten the fastening screw again. (see figures E5–E7)
– Repeat steps 3 and 4.
Focussing the Eyepiece
– Aim at a bright surface with the eyepiece 17 and adjust until
the crosshair is focussed.
To avoid a parallax when adjusting, please observe the following:
– When adjusting, direct the telescope at a target object.
– The crosshair and the target mark must not deviate from
each other, even when moving your eyes.
Note: Avoid a parallax, as exact measurements are otherwise
not possible.
In case a parallax occurs, repeat the adjustment as required.
Target Alignment
Horizontally
– Coarse Alignment
Loosen set screw 5 and aim at the target with the optical
peep sight 7.
Keep a certain clearance between your eye and the optical
peep sight.
Tighten set screw 5 again.
– Fine Adjustment
View the target through the eyepiece 17 and focus with ad-
justment screw 4.
Vertically
The target alignment in vertical direction is carried out analogue
with set screw 18 and adjustment screw 19.
Carrying Out Measurements
Measuring Horizontal Angles (see figure F)
– Switch the display on.
"Switching On the Display" see page 19.
– Position the measuring tool above measuring point A. "Set-
ting Up/Aligning the Measuring Tool" see page 21.
– Press the OSET button twice to set the indication for the hor-
izontal circle to zero.
– Direct the telescope against target point B.
The angle between points A and B is indicated on the display:
"HR" Counting direction clockwise
"HL" Counting direction anticlockwise.
Pre-adjusting Horizontal Angles
– Turn the measuring tool until the desired angle is indicated
on display "HR" or "HL", e.g., HR 60°00'00''
– Press the HOLD button twice.
The display indication flashes.
– Now, direct the measuring tool against the target point and
press the HOLD button again.
The display indication is shown continuous again.
The adjusted horizontal angle (e.g. HR 60°00'00'') thus cor-
responds with the starting point for the next measurement.
Measuring Vertical Angles (see figure G)
– Select the desired setting of the vertical-angle circle. ("Func-
tion setting" see page 20)
– Direct the measuring tool against a target point.
The vertical angle is shown on the display next to VA.
22 | English
Determining the Enclosed Inclination Angle:
– To determine the enclosed angle, direct the telescope
against a first target point and note down the indicated value
for the vertical angle.
– Afterwards, direct the telescope against a second target
point and subtract the indicated value for the vertical angle
from the value of the first target point.
By pressing the V/% button, you can change the inclination
readout to % or grad.
Measuring Distances (see figures H1–H3)
Distances can be measured with help of the stadia hairs sym-
metrical to the crosshair of the eyepiece.
– Position the measuring tool above measuring point A.
– Read off the length l with the crosshair and a levelling rod at
the target point B.
– Calculate the difference L with the following formula:
L = 100 x l
Accuracy Check of the Measuring Tool
(see figures I1 – I2)
Collimation is necessary in order to align the line of sight of the
telescope perpendicular to the horizontal axis of the instru-
ment.
Checking:
– Position the instrument with a clear view for 50 to 60 metres
on both sides of the instrument.
– Aim at point A over a distance of about 50 metres.
– Loosen only the vertical tangential screw and allow the tele-
scope to turn 180° around the horizontal axis so that it points
in the opposite direction.
– Loosen the horizontal movement clamp and tangential
screw, and turn the instrument 180° or 200 gons. Again de-
termine a visual point A, and tighten the clamp and screw.
– Loosen the vertical movement clamp and tangential screw,
turn the instrument 180° or 200 gons, and determine a visu-
al point C which should match the previous point B.
– If points B and C do not match, adjust them as described be-
low.
Adjusting:
– Unscrew the cover of the crosshair adjustment.
– Find point D between points C and B. It should be 1/4 of the
distance between points B and C, measured from point C.
The reason for this is that the preceding error of BC is four
times as large at the actual error because the telescope has
been turned round twice during the checking procedure.
– Move the vertical line of the crosshair so that it matches
point D by turning the left and right capstan adjustment
screws. Perform another check when adjustment has been
completed. If point B and C match, no further adjustment is
necessary. Otherwise, repeat the adjustment.
Note: To move the vertical line of the crosshair, first loosen the
capstan adjustment screw on one side, then tighten the capstan
adjustment screw on the other side by the loosened value. The
screws are loosened in an anti-clockwise direction and tightened
in a clockwise direction. Turn the screws as little as possible.
When the above-mentioned adjustment has been completed,
the following setting is necessary: Setting the Vertical Zero Po-
sition, page 23.
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