In this example the object is estimated to be 30m in
height
(H=30)
.
The altitude angle is measured in the reticle at 60
mils
(W=60)
.
Simply divide the height by the altitude angle to
determine distance.
30/60 = .5
The distance of the object is .5 kilometers from the
viewer.
Using the Vertical Reticle to Determine the Height
of an Object Using Altitude Readings:
You can calculate subject height using the following
formula:
H=D x W
H= Object height
D= Distance from the viewer
W = Altitude angle
First, estimate the distance from the object being
measured. Then, measure the altitude angle. Multi-
ply the distance in kilometers by the altitude angle
indicated by the reticle. This equals object height.
EXAMPLE:
The estimated distance from the viewer to the object
being measured is .6km.
The altitude angle is 60 mils (0-60)
H = .6 X 60 = 36m
The object height is 36m
Using the Horizontal Reticle to Determine the
Width of an Object Using Azimuth Readings:
You can calculate subject width using the following
formula:
W = D X L
EXAMPLE:
D = estimated distance from the viewer to the object
is .4km.
L = azimuth angle - which is 40 mils (0-40)
W = .4 X 40 = 16m
The object is 16m wide.
Using the Compass:
Azimuth angle can also be determined using the
compass which is built-in to the right half of the
binocular. It indicates azimuth (in degrees). Each
graduation mark on the compass scale indicates 1
degree. The compass scale is below the reticle and
is separate from it. However, the compass indicator
mark is in direct line with the center of the vertical
(altitude) reticle scale.
Identifying Compass Headings in Degrees:
North - 0 degrees (referenced as 360 degrees on
PENTAX Marine’s compass scale)
East - 90 degrees
South - 180 degrees
West - 270 degrees
In order to maintain accurate compass readings, the
binocular should be held horizontally and as level as
possible. This insures smooth fluid movement of the
compass indicator, and reduces “jumping”, “drag-
ging” or binding of the scale (which can cause errors
in readings). To increase accuracy, it is important to
allow the compass scale to settle to a complete stop
before attempting to determine headings.
Setting Your Position:
To verify your directional positioning (or bearings),
simply rotate your viewing position until “360” is
indicated in the center of the compass scale. This in-
dicates the viewer is facing due North. For the great-
est accuracy, always keep in mind the local variation
between magnetic and true North.
Locating the Heading of an Object:
To locate the heading of an object relative to your
position, simply align the vertical (altitude) reticle
on the object and read the heading on the compass
scale.
Compass Illuminator:
When ambient light levels are too low to see the
scale, the scale illuminator lamp must be employed.
However, in order to save battery power, do not use
the illuminator lamp when ambient light levels are
sufficient to see the scale.
