Optolong City Light Suppression Filter (CLS) 2" (50mm). CLS2
The CLS (City Light Suppression) broadband filters are designed to improve the visibility of various deep sky objects. By selectively reducing the transmission of wavelengths of light pollutants, specifically those produced by artificial lighting, 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 main nebula emission lines at OIII(496nm and 500nm), H-beta (486nm), NII(654nm and 658nm), H-alpha(656nm) as well as SII(672nm), this filter is suitable for enhancing the contrast and details for both visual and photographic purposes at sub-rural area. Main Use and Performance • Suitable for color CCD cameras and unmodified DSLRs. • CLS has a wider band pass than UHC and is more favored when observing under mild to moderate light pollution. • Light pollution filters do not eliminate the effects of light pollution or increase the object’s brightness. In many cases, they increase the contrast between nebula and night sky, not brightening the nebula. • WARNING: Optolong filters are not designed for sun observation. DO NOT LOOK AT THE SUN WITH OPTOLONG FILTERS. YOU WILL GO BLIND if you fail to observe the warning!