UHC(ultra high contrast), UHC is also a high-speed filter with an obvious effect on blocking harmful lights in the city. CLS filter selectively blocks lights, especially mercury and sodium light from synthetic lamps and the glow of nature. The CLS filter allows high transmission nebula light, it has high transmission in the region of OIII (496 nm and 500 nm), HFS (486 nm), NII (654 nm and 658 nm), HA (656 nm) and SII (672 nm). Our UHC effectively enhances the contrast of the nebula to ensure beautiful nebula details.

The OPTOLONG UHC filter provides excellent light transmission for a better view of deep sky objects, even for small telescopes. The high transmittance of our optical glass filters means there is enough light to allow for successful visual observation with 50mm telescopes. Our filters are optimized for use with the focal length of the telescope f/4 to f/15. Another major advantage of our UCH filter is the high optical quality of the filter glass. When using the OPTOLONG UHC filter, you will quickly notice the same sharp stars you know with your astronomical instrument without any filters.