center line on the mirror bisects the
(black) end of the compass needle. The
opening in the rear sight holder and the
instrument can be sighted by any of the
methods below.
the azimuth indicated on the azimuth scale
(1) R a i s e t h e r e a r s i g h t h o l d e r a p p r o x -
by the north-seeking
(white)
end
of
the
imately perpendicular to the face
compass needle.
of the compass. Sight on the object
e. Measuring Angle of Site. Hold the
through the opening in the rear
opened compass in a vertical plane with
sight holder (fig. 5) and through
the rear sight (fig. 6) toward the body and
the window in the cover. Keep the
the angle of site level lever to the right.
compass level and raise or lower
O p e n the cover to an angle of approximately
the eye along the opening in the
4 5o t o t h e f a c e o f t h e c o m p a s s . F o l d t h e
rear sight holder until the black
rear sight holder out parallel to the face
center line of the window bisects
of the compass with the rear sight per-
the object and the opening in the
pendicular to the holder. Look through the
rear sight.
rear sight and raise or lower the instru-
(2) F o l d t h e r e a r s i g h t h o l d e r ( f i g . 4 )
ment until the center line of the window
out parallel with the face of the
bisects the opening in the rear sight and
compass, with the rear sight per-
pendicular to its holder. Sight
through or over the rear sight and
view the object through the window
in the cover. If the object sighted
is at a lower elevation than the
c o m p a s s , raise the rear sight
holder as needed. The compass is
correctly sighted when the com-
pass is level and the operator sees
the black center line of the window
object sighted.
(3) R a i s e t h e f r o n t s i g h t a n d t h e e x -
tended rear sight assembly per-
pendicular to the face of the com-
p a s s . Sight over the tips of the rear
and front sights. If the object is
above the line of sighting, fold the
rear sight toward the eye as
needed. The instrument is cor-
rectly alined when, with the level
centered, the operator sees the
tips of the sights and the center of
the object sighted in coincidence.
d. Reading Azimuth Scale Directly. Hold
the compass in both hands at about waist
level, braced against the body, with the
rear sight away from the body. Open the
cover until the mirror affords a clear
image of the object sighted. Raise the rear
sight sssembly until it is approximately
perpendicular to the face of tie compass.
Level the instrument by means of the
circular level. Holding arms rigid with
the instrument level, turn body until the
4.
Compass
M2
observer's
view,
azimuth.
8