4.4 Centering with the optical plummet
After [4.3 Leveling with the plate vials] is completed, the instrument must be centered above the station point.
1Focus the optical plummet reticule by rotating the optical plummet eyepiece knob.
2Focus the station point by rotating the optical plummet focusing knob.
3Loosen the tripod center screw. Look through the optical plummet eyepiece, and move the instrument bottom plate until the reticule center coincides with the station point. (Take care not to rotate the instrument)
4Tighten the tripod center screw. Ascertain that the bubble stays positioned in the center when rotating the plate vial position in steps of 90°. If the bubble is not positioned in the center, adjust with the leveling screws. (Refer to [4.3 Leveling with the plate vial]).
Even if the bubble is shifted by one graduation in 4 , deviation of centering is just 0.3mm, at the instrument height of 1.4m, giving little effect on the survey result.
Center mark
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