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
as.
If the mirror reading determined in step ar. is
within 0.04 mil of the value displayed on the
mirror azimuth plate just below the reference
mirror window, then no adjustment is neces-
sary. If the error is greater than 0.04 mil, the
following adjustment procedures are to be
f o l l o w e d .
(1)
(2)
(3)
(4)
Subtract the last four digits of
the reverse reading from the last
four digits of the direct reading
(disregard the first two digits).
Divide this value by two to deter-
mine the collimation error.
Algebraically add the collimation
error to the value on the mirror
azimuth plate.
With the telescope in the direct
position, center the image
accurately in reticle pattern.
Adjust azimuth and elevation
controls as necessary to center
image. Using the horizontal cir-
cle adjusting tool (43), adjust the
micrometer and horizontal circle
(44) to the value calculated in
step (3).
2-90
