b. Correct the remaining 1/2 amount of the bubble displacement
with the leveling screws.
c. Revolve the instrument 180 or 200g around the vertical axis
once more and check bubble movement if the bubble is still
displaced, then repeat the adjustment.
11.2 Check and adjust vertical cross-hair
Check
Carefully level the instrument with the plate level. If the bubble
of the circular level is centered properly at this time, adjustment
is not required. Otherwise, proceed with the following adjustment.
Adjustment
Shift the bubble to the center of the level by adjusting three
capstan adjustment screws on the bottom surface of the circular
level with the accessory adjusting pin(see diagram).
22
o
11.3 Check and adjust vertical cross-hair
Adjustment is required if the vertical cross-hair is not in a plane
perpendicular to the horizontal axis of the telescope (since it
must be possible to use any point on the hair for measuring
horizontal angles).
adjustment screw
tribrach
bubble
