The 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 Na (sodium) and Hg (mercury) wavelengths mainly emitted by urban night lighting or undesirable natural light (atmospheric oxygen radiation, etc.), while allowing the main wavelengths from celestial objects. The anti-light pollution filter is particularly useful for improving the brightness of deep sky objects: nebulae, star clusters, galaxies, etc. It is especially effective on emission nebulae because of the filtered wavelengths. Examples of emission nebulae: Bubble (NGC 7635), Crescent (NGC 6888), Eagle (M16), Elephant’s Trunk (IC 1396), Flame (NGC 2024), Lagoon (M8), North America (NGC 7000), Omega (M17), Orion (M42), Pacman (NGC 281), Rosette (NGC 2237), Tarantula (NGC 2070), Thor's Helmet (NGC 2359), Trifid (M20), Tulip (Sh2-101). Designed specifically for the Vespera lens, it fits easily and discreetly into the optical arm. The lens ring that holds the CLS filter is equipped with an electronic card that allows Vespera to detect it. The filter is delivered in a transparent storage box.
