Instruction manual

38
8.3 Adjustment of the Vertical Cross-hair
Adjustment is required if the vertical cross-hair is not in a place perpendicu-
lar to the horizontal axis of the telescope ( since it must be possible to use
any point on the hair for measuring horizontal angles or running lines).
● Checking
1
Set the instrument up the tripod and carefully level it.
2
Sight the cross-hairs on a well defined Point A at a distance of, at
least, 50 meters (160ft.) and clamp horizontal motion.
3
Next swing the telescope vertically using the vertical tangent screw,
and check whether the point travels along the length of the vertical
cross-hair.
4
If the point appears to move continuously on the hair, the vertical
cross-hair lies in a plane perpendicular to the horizontal axis ( and
adjustment is not required ).
5
However, if the point appears to be displaced from the vertical
cross-hair, as the telescope is swung vertically, then proceed with
the following adjustment.
● Adjustment
1
Unscrew the cross-hair adjustment section cover, by revolving it in
the counterclockwise direction, and take it off. This will expose four
eyepiece section attachment screws.
2
Loosen all four attachment screws slightly with the accessory screw-
drive (while taking note of the number of revolutions).
Then revolve the eyepiece section so that the vertical cross-hair
coincides to Point A’.
Finally, re-tighten the four screws by the amount that they were
loosened.