Centering - Nikon DTM-502 Series Instruction Manual

2-4. Centering

"Centering" refers to the precise alignment of the instrument's central axis over the
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station point. This can be accomplished in two ways, through the use of a plumb
bob, or the optical plummet.
1) Using Plumb Bob
(1) Place the instrument on the tripod head. Insert the tripod mounting screw
into the center hole of the instrument's base plate and tighten.
(2) Hang the plumb line on the hook of the tripod mounting screw and adjust the
length of the plumb line to the position the tip of the plumb bob at the height
approximately level with the station point.
(3) Slightly loosen the tripod mounting screw. Supporting the outer side of the
leveling base with both hands, carefully slide the instrument about on the
tripod head until the tip of the plumb bob is perfectly positioned over the
center of the station point.
• Confirm precise alignment by viewing from two directions at right
NOTE
angles to each other.
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