Optolong 82mm Clear Sky Round Mounted Filter
Optolong has created the Clear Sky Filter in order to reduce wavelengths notorious for artificial light pollution, such as Na and Hg light pollution. As shown in the photos above, this filter dramatically increases contrast and prevents excess light from reaching your camera sensor. With the Optolong Clear Sky filter, there is no wavelength shifting or gradient images.
Housed in a round 82mm CNC-machined cell, the Clear Sky filter can be threaded directly onto the front of your camera lens, like UV lens. The filter itself is made of premium optical glass for quality you can see.