This Optolong CLS Deep-Sky high contrast filter for CCD imagers is specifically designed for improving contrast of nebulae, galaxies and star clusters with astronomical instruments of any size.
This broadband filter greatly improves visibility of various deepsky objects by selectively reducing the transmission of wavelengths of light pollutants, specifically those produced by artificial lightings including mercury vapor lamps, both high & low pressure
sodium vapor lights and the unwanted natural light caused by neutral oxygen emission in our atmosphere (i.e. skyglow).
Together with the highly transparent in main nebula emission lines at OIII(496nm and 500nm), H-beta (486nm), NII(654nm and 658nm), H-alpha(656nm) as
well as SII(672nm), the filter is suitable for enhancing the contrast and details for photograghic purpose at light pollution area.
The filter essentially blocks the light in the spectral lines of mercury and sodium-vapor lamps while letting the largest part of the visible light and H-alpha emissions pass. All the important emission lines, as well as the spectral region that "well dark adapted eyes" can see, will pass through this excellent allround use filter.
Glass thickness: 2mm