The filter is suitable for observing weak and low contrast deep objects. These features make it ideal for observing nebula objects such as nebulae. It can be used not only for astronomical observations but also for astronomical photography Substrate: precision polished substrate, good parallelism and surface precision.Double-sided fine polishing and polishing process ensures high parallelism Coating: double-sided multi-layer coating, the backside increases the broadband penetration film and reduces the reflected light Ultra-high contrast filter (UHC filter) is the choice of harmful light filter, such as glare and ghosting, so that vision is more perfect. Significantly reduce light pollution, suitable for urban and suburban observation The 1.25-inch UHC telescope filter is designed to improve the image contrast of the subject. Diameter: 1.25 " simply attached to the eyepiece, installed in a solid and transparent shell