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 K S
SERVICE (Continued)
o.
If the mirror reading determined in step n. 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
f o l l o w i n g a d j u s t m e n t p r o c e d u r e s a r e t o be
f o l l o w e d.
( 1 ) S u b t r a c t t h e l a s t f o u r d i g i t s of
the reverse reading from the last
four digits of the direct reading
(disregard the first two digits).
( 2 ) D i v i d e t h i s v a l u e b y t w o t o
d e t e r m i n e t h e c o l l i m a t i o n
error.
( 3 ) A l g e b r a i c a l l y a d d t h e c o l-
limation error to the value on
the mirror azimuth plate.
( 4 ) W i t h t h e t e l e s c o p e i n t he
d i r e c t p o s i t i o n , c e n t e r t h e
image accurately in the reti-
c l e p a t t e r n . A d j u s t a z i m u t h
a n d e l e v a t i o n c o n t r o l s a s
n e c e s s a r y t o c e n t e r i m a g e.
U s i n g t h e h o r i z o n t a l c i r c le
adjusting tool (1), adjust the
m i c r o m e t e r a n d h o r i z o n t al
c i r c l e ( 1 ) t o t h e v a l u e
calculated in step 3.
2-74
