SVBONY SVBONY Telescope Filter 1.25 inches CLS Filter City Light Pollution Reduction Filter Broadband Filter Suitable for Deep Sky Visual Astronomical Photography

Evaporation with Ion assisted deposition coating technology for durability and resistance to scratching;as well as stability on CWL (central wavelength) no deviation affected by temperature change Planetary rotation system offers precision and homogeneity of coatings ensuring high value on transmission of pass-band and Optical density of off band 90% transmission of main nebula emission lines;such as Ha 656nm;OIII 496nm;500nm;SII672nm and H-beta 486nm 0.1% transmission of off-band;specifically the major emission lines of artificial light pollution;such as Na 589nm;Hg 435nm and 578nm Suitable for color CCD cameras and unmodified DSLR Urban optical filter can effectively suppress urban harmful light and improve the contrast of shooting target