Orion 5659 2-Inch SkyGlow Broadband Eyepiece Filter The SkyGlow filter enhances deep-sky observing in moderately light-polluted skies 2" eyepiece filter blocks the most common wavelengths of light pollution for increased contrast and better view quality SkyGlow improves the views of nebulas, galaxies and star clusters, especially when viewing in areas with light pollution from streetlights and sources Ideal for backyard astronomy observing when you don't have time to trek to a dark sky site 2" filter designed for use with 2" telescope eyepieces. Metal filter cell construction.