The filter's 2mm thick glass and fine optical polish allow it to be inserted into the optical path without degrading the image quality, even when used in front of a binocular viewer. The substrates are free of striae and plane-parallel polished to within 30 seconds of arc, eliminating any double images or ghosting due to wedge errors in the glass. The filter cell features the largest clear aperture of any telescope filter on the market, ensuring complete freedom from vignetting at any focal length. The front "crown" incorporates milled notches for easy handling and threading in the dark.
All surfaces of this radiant filter are treated with a 7-layer Multi-Coating, resulting in a mere 0.25 % residual reflection. This is the most elaborate coating ever applied onto amateur color filters, ensuring a filter free of any false reflections under any incident angle of light. Light is the most crucial element for all planetary observation. The 7-layer MC-coatings not only provide a brighter image, but they also prevent the softening effect of scattered light, which can obscure the subtlest planetary surface details. With painstaking attention to coatings and perfect optical figuring, the image contrast through these premium filters is rock-solid, making your astrophotography experience truly unforgettable.


