The SVBONY 7nm dual band filter is designed to drastically reduce the effect of light pollution, for emission nebulae, planetary nebulae and supernova remnants imaging. The 7nm bandwidth strongly isolates the nebulae's emissions into H-Alpha (red) and OIII (green-blue) from anything else, ensuring that the shooting astronomical object is pure enough, free from non-target spectral interference. Comparing to the traditional DSO photography plan "Monochrome camera + SHO filters + Filter wheel" and long single channel exposure time and post-processing, SV220 dual-band filter simplifies the tediousness and difficulties of photography and post-processing, gaining full color images with one-shot. The SV220 filter greatly reduces the effect of light pollution and moonlight, and makes it possible to do photography in a light polluted environmental conditions, like on your balcony or in your backyard. Meanwhile it saves your time on the road and cost on the fuel.