This 1.25" L-Pro Deep-Sky Light Pollution Filter by Explore Scientific is the perfect way to get the most out of your night sky. By blocking out artificial light sources, this filter allows you to see more stars and other deep-sky objects in your view, giving you a clearer, brighter, and more detailed look at the night sky. The filter is designed with a multi-layer coating to reduce the effects of light pollution and maximize the performance of your telescope.