Zipp02 | 18Preparation before Measurement
not to turn the instrument) so that the ground point coincides with the
central point of the reticle. Retighten the central screw.
2. Perform precise leveling up of the instrument as described in "3.3 Leveling
up of the Instrument" and repeat the operation in 1. of "3.4 Centering",
"Centering with Optical plummet" until the instrument is precisely leveled
up and the center of the reticle of the optical plummet precisely coincides
with the ground point as shown.
3.5 Collimation
Adjustment of
diopter
1. Aim with the telescope on a bright background.
2. Turn the eyepiece knob so that the cross hairs of the reticle are clearly
seen.
Elimination of
optical parallax
1. Adjust the focusing knob so that the object forms image on the reticle.
2. Move your eyes up and down to see if the image of the object moves rela-
tive to the graduation lines.
If it does not move, there is no optical parallax; otherwise turn the focusing
knob to eliminate the optical parallax.