"The Baader Planetarium FFK-1 Fringe-Killer Filter provides the brightest image of all color-correcting filters currently on the market. The Baader Fringe-Killer Filter minimizes unwanted blue fringing, comparable to a Minus-Violet-Filter, while retaining a very pleasing color balance. This is only made possible by applying modern DWDM plasma-assisted coating technology, allowing almost a hundred coating layers to be accumulated onto a planoptically polished substrate without destroying the optical figure. This fine optical tool will help a small refractor achieve the magnification advertised on the box. Performance rivals that of the most expensive color correcting lens systems, costing 20 times more.The coatings required to accomplish this innovative filtration are exceedingly complex, requiring almost 50 layers per side, using the latest DWDM Plasma assisted coating process. The Fringe Killer has perhaps the most complex coating ever achieved on an amateur astronomical filter. The Fringe Killer is the perfect compliment to the Baader Contrast Booster. The Contrast Booster is an aggressive filter, designed to deliver the maximum sharpness and contrast possible from an achromat. The result is complete removal of the violet haze, with a somewhat dimmer and yellowier image. The Contrast Booster also incorporates additional RGB filtration for further enhancing color contrasts. Digital Imagers (CCD, DigiCam and webcam) will find the Fringe Killer to be the ultima|Built-in Infrared Blocker (656 nm to 1150 nm) - great for CCD work or projection photography of the Moon and planets with digital cameras|The Baader Planetarium Fringe-Killer Filter is fully threaded and designed for 1.25"" oculars|The Baader Planetarium Fringe-Killer Filter removes unwanted blue and purple image fringing while still retaining a pleasing color balance|Plasma-assisted coating technology allows application of 50 coating layers on the glass without destroying the optical figure|Offering the brightest image of all color-correcting devices in the industry, makes the Fringe-Killer a must for even the smallest of refracting (lens type) telescopes|Removes blue fringing as well as RED fringing above 656 nm|Forms a ""plateau"" of eff. 50% transmission in the blue spectral region from 450 nm to 480 nm, which is much more complex to produce than even the narrowest of all Nebula Filters|Retains the highest light transmission of all known color correcting devices - be it filters or lenses - in all important deep sky wavelengths from 486/501 up to 656 nm|Built-in Infrared Blocker, ranging from 656 to 1150 nm, makes it the perfect tool for CCD work, as well as afocal projection photography with digital cameras for the Moon and planets|The most subtle of color variations remain visible in planetary surface detail, due to the excellent color balance|Combine with the Baader Red 610 nm color filter to receive an ultra narrow (-70 nm) wide H-Alpha passband filter at an amazing 95% peak transmission|Combine with the 1.25"" Skyglow Filter for breathtaking contrast on lunar and planetary surface detail|Planoptically polished to achieve perfect sharpness, even when mounted way in front of a binocular viewer, or during afocal projection (digital imaging)|No deterioration of resolution with magnification at 300 times or more, something that would not happen with the usual ""flame polished"" (raw polished) glass, commonly used for a wide variety of filters|Plasma-assisted, hardest, scratch proof and water impermeable dielectric coatings of almost 50 coating layers on either side, most carefully designed to extend equal tension onto either side of the substrate in order to retain the highest quality opt"