Optical devices come to the aid of man, expanding the horizons of the visible, increasing human capabilities when observed in the daytime and in twilight. They are used for research and observations, to search for and navigate to work and during leisure time.
Dusk reduces the sensitivity of the human eye, shifting in the area of short-wave radiation, and natural night illumination by the spectrum tends to shift toward long waves
And lack of natural abilities to see in the dark prompted him to create a special optical instruments, night vision devices.