6.5. Visibility decreases and / or disappears.
Bright light sources (moon, projectors or headlights) may result in visibility degradation or even complete disappearance. If this happens move the scope away from the light source immediately. The image should be restored in within 2 minutes.
Poor atmospheric conditions such as fog, haze or extremely dark environments, will decrease the visibility distance as well.
6.6. Visible spots
Image quality of the object, which is being observed when an image intensifier is functioning, depends mainly on operating characteristics of this image intensifier.
Due to this fact black spots, which are inherent in the image intensifier, may be seen in the field of view of a viewing device. Field of view is shown below.
Central zone
Boundary zone
Periphery zone
Acceptable defects, which may be seen in the field of viewing device, are given in the table
10
