It can be used not only for universe observations but for astrophotography 95%transmission of main nebulas lines and 0.1% transmission of offband specifically the majors lines of artificial light pollution Precise polish substrates good parallelism and precise ensures you used long time The UHC filter is designed to improve the images contrast of observed objects Including a box to carry and storage Great for city and suburban observation Double sided multi layer coating and the backside increases the broadbands penetration film reduces the reflecting light and increases the contrast and images sharpness Optical glass lens; Aluminum frame