TM 5-6675-322-14
(1) Position micrometer at midscale .
( 2 ) P o s i t i o n l e f t o p t i c a l d o t o v e r p o i n t A.
( 3 ) L i f t a d j u s t m e n t p i n a n d p o s i t i o n r i g h t o p t i c a l g l a s s m o u n t a t a d j u s t m e n t
hole closest to point A1.
( 4 ) P o s i t i o n l e f t o p t i c a l d o t o v e r p o i n t A .
Unlock locking lever on micro-
meter.
T h e n t u r n k n u r l e d k n o b o n micrometer to left or right until right optical
dot is over point A1.
c .
Make datum plane reading.
(1) Choose known elevation point that is on both photographs (or point that
w i l l b e a t r e f e r e n c e e l e v a t i o n ).
( 2 ) P l a c e l e f t o p t i c a l d o t o v e r t h i s p o i n t o n l e f t p h o t o g r a p h.
(3) Place right optical dot over same point on right photograph.
(4) Look through stereoscope and turn micrometer knurled knob until two
optical dots are seen as one dot that looks as if it contacts ground on reference
p o i n t.
d.
Read micrometer scale.
4-9
