Prepared By: Tim Wojo
Revision: 1-050309
Page 7 of 9
40-6910 Service Manual
2.2 Line of Site Verification/Calibration
Once Vial calibration has been verify/achieved, it is necessary to verify/calibrate the line of site. Essentially this assures that the
stadia lines with in the telescope (cross hairs) are on the same plane as your reference. This can be done a number of ways:
By purchasing an automatic level/collimator.
By comparing the test instrument to a
known good
reference laser,
theotolite, etc.
Using the long shot, short shot method.
Regardless of the method, calibration adjustments are the same. This manual
only discusses verification using an automatic level.
Setup the instrument as shown in figure F, level the bubble, and focus the lens
until you can clearly see the stadia lines inside the collimator tube. If the
center horizontal hair on the stadia lines of the instrument is not coincident
with the horizontal reference line on the of the collimator tube, the instrument
should be calibrate using the method below.
1. Remove rubber cover 3 (3) to expose calibration set screws 6-6 and 6-16.
2. Using a 1.5mm Allen wrench, loosen calibration set screws 6-6 and 6-16.
3. Rotate the eyepiece seat to make the crosshair center on the reticle of instrument on the same level with crosshair center on
the reticle of collimator tube. Then rotate the eyepiece tube to make the horizontal hair on the reticle of intrument level.
Now the middle horizontal hair on the reticle of the instrument coincide with the horizontal line on the reticle of the
collimator tube.
4. Tighten the two set screws 6-6 and 6-16 and restore rubber cover 3 (3) to its original position.
Figure F
Leveling accuracy using
an automatic level
Eyepiece tube
Eyepiece seat
Figure G
