Noblex NF 7 x 50 C inception User Manual page 19

If the target object to be measured is larger than the scale area of the grati-
cule, 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 indi-
vidually 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 graticule
(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.
1,200 m x 6.0
Lighthouse height ( m ) =
= 72 m
Result:
100
Distance ( m ) x Elevation
Height of the target object(m) =
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 determined, if
one knows the distance to it.
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