• 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 435nmand 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