Proven performance across the spectrum.
Light pollution is often caused by sodium-vapor street lamps which emit light at 589 nm on the visible spectrum and cast an orange hue. The Autumn & Night Sky filter has a sharp dip in light transmission around 589 nm to decrease the effects of sodium-vapor bulbs while still maintaining high transmission from 600-700 nm. Smaller decreases in % transmission from 400-550 nm are meant to counteract different types of light sources that interfere with nighttime photography.
Despite the decreases in transmission to block orange hues, the Autumn & Night Sky filter has higher average light transmission throughout the visible range than other night sky filters on the market.