Lumicon 1.25 Inch Deep Sky Filter (2nd Quality)2nd Quality Filters have minor blemishes that will not matter in visual use. Lumicon 1. 25 Inch Deep Sky Filter Lumicon 1. 25 Inch Deep Sky Filter is the best all purpose nebula filter on the market today. It blocks all high & low pressure mercury and sodium vapor lamp light, neon lights and air glow, while transmitting the rest of the visible spectrum. Visually, Lumicon 1. 25 Inch Deep Sky Filter enhances contrast of nebula under both light polluted