Table of Contents
Advertisement
Wahl DHS520
6.0 OPTICS
The Wahl DHS520/520B has a precision reflex optical system, which provides
user-focusable 'through the lens' sighting and gives precise definition of the
target spot. The specified focal range is 1m/39.4in to infinity.
6.1 Target Size Calculation
The precision reflex optical system gives a narrow field of view (180:1 to 98%
energy).
As the instrument is focusable, you can calculate an approximate target size
from the information given in Fig. 15.
target diameter (T) (mm) = target distance (D) from optical datum (mm) - 100
target diameter (T) (in) = target distance (D) from optical datum (in) - 4
Fig. 15 Wahl DHS520/520B thermometer target size calculation
target distance (D) from optical datum
field of view
optical
datum
field of view (180)
or
field of view (180)
User Manual
target size (T)
Not to scale
315015
Page 11
Advertisement
Table of Contents
