Vaonis Vespera Light Pollution FilterThe Vespera light pollution filter or CLS (City Light Suppression) filter allows you to improve the quality of your photos when observing in the city or suburbs. It attenuates the effects of light pollution and thus increases the contrast between the celestial object being photographed and the background sky. The broadband filter blocks wavelengths mainly emitted by urban night lighting or undesirable natural light, while allowing the main wavelengths