The significance of night sky natural radiation to the low-light night vision device is that in the low-light night vision device, the infrared light in the natural light is used as the working light source. Since the human eye is sensitive to different wavelengths of light, we cannot see visible light, but we can perceive infrared light. Natural radiation at night refers to the infrared light from nature at night without the interference of artificial light sources. The significance of the natural radiation of the night sky to the low-light night vision device is that the infrared light in the natural light can penetrate the atmosphere and the surface of the earth and reach a certain height above the observation target, so it can be used as the working light source of the low-light night vision device, thus helping night vision. The sight instrument observes objects in dim light.