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Performance Steps
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1.
Read your compass (figure
C-19).
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Figure C-19 Lensatic compass
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a.
The floating dial is used to
determine the direction in which you
are pointing your compass.
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b.
The outer, black ring of
numbers and tick marks are used for
finding direction in mils (figure
C-20).
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Figure C-20.
Lensatic compass floating dial
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c.
The inner, red ring of numbers
and tick marks are used for finding
direction in degrees.
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(1)
There are 360 degrees or 6400
mils in a circle. These are marked
with a tick mark every 5 degrees or 20
mils. However, not every tick mark is
numbered. You will have to determine
the number for these lines using the
numbers that are shown.
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(2)
To read direction, point the
compass in the direction you want to
go or want to determine.
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(3)
Look beneath the index line on
the outer glass cover and estimate to
the nearest degree or 10 mils the
position of the index line over the
red or black scale.
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(4)
Be careful to hold the compass
still so that the dial remains
stationary while you are reading the
scale.
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(5)
If you understand these
readings and can apply either of the
holding and sighting techniques of
shooting an azimuth, you will be
proficient in performing this task.
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2.
Shoot an azimuth.
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a.
Use your compass to determine
or follow an azimuth. The arrow on the
compass points toward magnetic north.
The arrow is also attracted by any
mass of metal; for example, a truck,
your rifle, your helmet, and even
electrical power lines. Thus, be sure
you use your compass away from metal
objects so it will not give a wrong
reading.
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b.
The lensatic compass must
always be held level and firm when
sighting on an object and reading an
azimuth.
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c.
There are two methods of
holding the lensatic compass and
sighting.
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(1)
Compass-to-cheek method (figure
C-21). To use this method-
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(a)
Open the cover to a 90-degree
angle to the base. Position the
eyepiece at a 45-degree angle to the
base.
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(b)
Place your thumb through the
thumb loop, form a steady base with
your third and fourth fingers, and
extend your index finger along the
side of the compass base.
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(c)
Place the hand holding the
compass into the palm of the other
hand.
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(d)
Bring both hands up to your
face and position the thumb that is
through the thumb loop against the
cheekbone.
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(e)
Look through the lens of the
eyepiece. If the dial is not in focus,
move the eyepiece up or down until the
dial is in focus.
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(f)
Align the sighting slot of the
eyepiece with the sighting wire in the
cover on the point for which the
azimuth is being determined. Look
through the lens of the eyepiece and
read the azimuth under the index line.
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Figure C-21
Compass -to-cheek method
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(2)
Center-hold method (figure
C-22). To use this method-
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Figure C-22. Center-hold method
Note. This method is used only when a precise direction is not
required.
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(a)
Open the compass so that the
cover forms a straight edge with the
base. The lens of the compass is moved
out of the way.
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(b)
Next, place your thumb through
the loop, form a steady base with your
third and fourth fingers, and extend
your index finger along the side of
the compass.
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(c)
Place the thumb of the other
hand between the eyepiece and lens,
extend the index finger along the
remaining side of the compass, wrap
the remaining fingers around the
fingers of the other hand, and pull
your elbows firmly into your side.
This will place the compass between
your chin and your belt.
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(d)
To measure an azimuth, turn
your entire body toward the object and
point the compass cover directly at
the object. Look down and read the
azimuth from beneath the fixed black
index line. This method can be used at
night.
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(e)
To keep from going in circles
when you are land navigating, stop
occasionally to check the azimuth
along which you are moving. Also, you
can move from object to object along
your path by shooting an azimuth to
each object and then moving to that
object. Repeating this process while
you navigate should keep you straight.
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