a. Unscrew the cross-hair adjustment section cover by revolv
-ing it in the counter-clockwise direction. this will expose four
eyepiece section attachment screws.
b. Loosen all four attachment screws slightly with the accessory
screw-driver(while taking note of the number of the revolutions).
Make vertical cross-hair coincide with A by turning eyepiece
and tighten the four attachment screws.
c. Check if there is displacement in horizontal direction while point
A travelling along vertical cross-hair. if not, check it concluded.
11.4 Collimation of the instrument
Collimation is required to make the line of sight of the telescope
perpendicular to the horizontal axis of the instrument.
Check
a. Set the instrument up with clear sights of about 50 to 60
meters of both sides of the instrument.
b. Sight point A at approximately 50 meter distance.
c. Loosen the vertical tangent screw only and plunge the tele
-scope 180
°
around the horizontal axis so that the telescope
is pointed in the opposite direction.
d. Sight point B, at equal distance as point A.
e. Loosen the horizontal motion clamp and tangent screw and
revolve the instrument 180
°
or 200gon. Fix a sight on point
A once more and tighten the motion clamp and screw.
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