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ENGLISH
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 grati-
cule (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 measure-
ment 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.
