Fog is one of the many enemies of amateur astronomers. In a cold or humid environment, droplets and fog can form on the lens of telescopes and cameras, affecting both the quality of observation and photos.
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.
The Vespera Dual Band Filter is a dual narrowband interference filter that will significantly improve your photo quality whether you are viewing from an urban or natural environment.