TM 5-6675-250-10
2-7. OPERATING PROCEDURE - Continued
ALIGNMENT OF THEODOLITE HORIZONTAL CIRCLE TO REFERENCE MIRROR - Continued
i.
If the vernier scale does not appear under
the fixed index, adjust the micrometer
control to position the fixed index mark of
the horizontal scale to the center of the
second nearest double line.
Record the horizontal scale reading as fol-
j.
lows:
(1)
If the fixed index is over a three-digit
n u m b e r , record the number as it
appears and add a zero as the fourth
digit.
(2)
If the fixed index is over a number
five, record the preceding three-digit
number and add a five as the fourth
digit.
k.
Record the vernier scale reading. Exam-
ples of vernier scale readings are shown
below.
2-40
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