Armasight DAB10X42RF0ARM1 10x42 Binoculars - Manual (Page 13)

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2) How to Measure the Vertical View Angle
Upper and lower angle means the angel included between any two targets (or two ends of the target)
against the vertical line on the reticle.
A. Vertical View Angle measurement is similar to measuring the Horizontal View Angle. When the Verti-
cal View Angle measurement is small, aim the cross center of reticle at lower part of the object, read the
scale value at the top of the object. If the target vertical angle is a little bigger, you can read the upper
scale and the lower scale. As shown in Figure 12, the upper line is 35mils, and the lower line is 40mils,
the total vertical angle is 75mils.
B. When the Vertical View Angle is larger than the vertical scale range (-50 to +50 mils), it can be mea-
sured in steps and the angle can be obtained by summing up the value of each step. (The process will
be similar to the measurements as mentioned above as horizontal view angle.)
3) How to Use the Reticle to Measure Distance.
The distance measurement of a target can be calculated by using the mil reticule.
The formula of distance measurement: L(km)= H (m)/ω
L — the distance between the observer and the object (km)
H — the height of the object (m)
ω — the View angle of the object measured with the reticule of binoculars (mil).
When measure the distance, first, estimate the width or height of the object, then measure the View
Angle of the object. According, you can calculate the distance between the observer and the object
using the formula.
For example 1:
There is an lighthouse height is 25m (H = 25m).
The Vertical View Angle of the adult is 6 decade mils (60mils).
Figure 11. Measuring of big View Angle
Figure 12. Vertical View Angle Measuring