About the Optolong L-Pro Light Pollution Filter
This L-Pro (L-Professional) filter is 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 lights including mercury vapor lamps, both high and 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 O-iii(496nm and 500nm), H-beta (486nm), N-ii(654nm and 658nm), H-alpha(656nm), as well as S-ii(672nm), the filter is suitable for enhancing the contrast and details for both visual and photographic purposes from sub-rural areas with heavy light pollution.
Compare the L-Pro, L-eXtreme, and L-eNhance filter transmission lines:
Unlike other light pollution filters (UHC and CLS,) L-Pro is a multi-bandpass filter offering excellent color balance by maximizing the transmission band. The balanced transmission allows astrophotos to be taken with minimal color cast to broadband emission objects such as galaxies, reflection nebulae, and globular star clusters. L-Pro is the best choice for light pollution suppression.
Main Use and Performance
Suitable for visual observation and astrophotography.
The L-Pro filter has a very low transmission reduction rate against continuous spectrum space objects and thus is quite effective in suppressing light pollution sources when shooting galaxies, reflection nebulae, and globular star clusters. The same holds true for visual star observations.
L-Pro filters alone can suppress infrared wavelengths, and thus can be used at ease for “L” image shooting with CCD cameras. 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.
MANUFACTURER'S WARNING: The filters of Optolong are not designed for sun observation. DO NOT LOOK AT THE SUN WITH OPTOLONG FILTER.