TM 5-6675-250-20
2-16. DETERMINATION OF AZIMUTH VALUE FOR REFERENCE MIRROR (Continued)
L O C A T I O N / l T EM
A C T I ON
R E M A R KS
a q.
Obtain reverse readings by doing the follow-
ing:
(1) Release the vertical lock
(40) and rapidly rotate
telescope 180 degrees about
the horizontal axis; tighten
the vertical lock.
(2) Release the horizontal lock
(41) and rotate the theodolite
alidade 180 degrees
(clockwise); tighten the
horizontal lock.
(3) Record the reverse horizon-
tal and vernier scale
readings in the same man-
ner as used for direct
r e a d i n g s.
(4) Add horizontal and vernier
scale readings to obtain
reverse horizontal reading.
2-88