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ENGLISH
a)
b)
Using the reticles for rangefinding
The integrated graticule serves for determination of distance of distant
objects.
If the height or length of the target object is approximately known, the
distance can be determined using the following formulas:
Distance(in m) =
Height of the target object (m) x 100
Elevation of the target object(°)
=
Length of the target object (m) x 100
Azimuth of the target object(°)
Elevation = vertical angle
Azimuth = horizontal angle
Example:
The object height of the pictured lighthouse is 60 m. For the height
of the lighthouse, the value 6.0 can be read on the graticule.
Result:
Distance (m) =
60 m x 100
6.0
≈
1,000 m
If the target object to be measured is larger than the scale area of the
graticule, a feature of the object (chimney, mast, etc.) can also be used for
the calculation. It is also possible to proceed step by step and to add up the
individually determined values step by step.
Measurement of elevation (vertical angle) for determining the object height
The elevation angle indicates the angle between the horizontal on which the
observer stands and a particular point on the targeted object (e.g., the top
of the lighthouse). If the elevation angle is within the scale value of the grat-
icule (8 mil), then the vertical zero mark of the scale should first be aligned
with the base of the lighthouse in order to easily read the angle.
Example:
The prerequisite is that the distance to the target object is known. In this
example, the distance to the lighthouse is 1200 m and the scale value read
on the graticule is 6.0.
Result:
Leighthouse height (m) =
1,200 m x 6.0
100
= 72 m
Height of the target object(m) =
Distance (m) x Elevation
100
Measurement of the azimuth = horizontal angle for determining the object length
The measurement of a horizontal visual angle is similar to the measurement
of the vertical visual angle. For this purpose, the horizontal graticule scale is
used. For narrow objects, the long vertical line must be moved to one edge
of the object and the azimuth of the object can be read directly on the scale
on the other edge of the object (s. Fig., here, e.g. it is 2 mil). In the case of
wider objects, any line of the horizontal scale must be moved to one edge
of the object and, on the other scale side, the value at the other edge of the
object must be read. Now, the azimuth can be obtained by adding the two
scale values. On this basis, the length or width of any object can be deter-
mined, if one knows the distance to it.
Summary of Contents for NF 7 x 50 advanced
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