Ice Reduces Light Pollution in Night Sky, Absorbs Yellow Sodium-Vapor Light, 1.25x Filter Factor, +0.3 Stop, Optical Glass Construction, Slim, Aluminum-Alloy Filter Ring, 77mm Front Filter Threads, Knurled Sides, Plastic Case, The Ice 77mm Lipo Light Pollution Filter is designed to reduce the appearance of light pollution in images or video that include the night sky and illumination from artificial light sources. This effect can be obtained when this filter is used on a film camera system with daylight film installed or on a digital camera system with its daylight white balance setting selected. Light pollution occurs in areas of the night sky that are above or near concentrated and intense sources of artificial light such as cities. These light sources can include exterior and interior lamps for commercial or residential buildings brightly lit advertisements such as billboards streetlamps as well as sports and entertainment venues. Together they can result in a type of light pollution known as skyglow where individual stars the Milky Way and other astronomical features in the night sky are obscured. Additionally artificial lights clustered together can become difficult to individually discern. Light pollution from these cluttered sources can become a source of distraction within an image and can resemble overexposed areas of glare. When used the Ice 77mm Lipo Light Pollution Filter can improve the results of nighttime images by absorbing the yellow light from sodium-vapor lamps a common light source within urban areas. By preventing the dominant wavelengths of light associated with the color of those lamps from being recorded the visibility of astronomical objects is enhanced and artificial light sources are more clearly defined with less glare and improved contrast. This filter is constructed from optical glass for clarity as well as color fidelity. It features a slim aluminum-alloy filter ring that helps prevent vignetting while remaining durable and lightweight., ICE-LP-77 LP77