"The Baader Planetarium Moon and Skyglow (Neodymium) filter brings an entirely unique approach to planetary contrast enhancement and light pollution reduction. Based on earlier research at Carl Zeiss, Baader has developed a new filter that uses Neodymium glass, which filters out a few specific wavelengths from streetlights as well as skyglow from the Moon. The unique spectral characteristics of Neodymium also boost color contrasts by isolating the Red, Green and Blue regions (so-called RGB enhancement). The result is a filter that leaves natural colors mostly intact, but significantly enhanced.The filter substrate is a special custom melt of Neodymium doped glass, designed for specific transmission characteristics and made only for Baader Planetarium. In addition to its unique spectral characteristics, unlike most filters, the Baader Moon and Skyglow surfaces are optically polished to deliver the best possible image sharpness and contrast."