* As Reviewed in the April 2004 Sky and telescope *
Achromat owners rejoice! Baader Planetarium has taken minus violet filtration to a new level. The Fringe Killer brings a type of filtration, never before seen, to the amateur. Rather than simply trimming the shorter wavelengths at a chosen wavelength and slope like all other minus violet filters, the Fringe Killer carefully attenuates a specific region of the spectrum. This allowed Baader to tune the filter for maximum practical reduction of the most damaging defocused blue wavelengths, with only a faint yellow color shift - without dimming and lowering image contrast by resorting to reduction of the important green-yellow wavelengths to crudely restore an apparent color balance! (where the eye is very sensitive, and where refractors are their sharpest) The result is a filter that removes the majority of color fringe, without affecting image brightness all, imparting strong coloration, or reducing contrast at important wavelengths. As any telescope owner knows, light is a valuable commodity for both planetary and deep sky viewing, and the fringe killer preserves every bit of light possible.
Terrestrial observers will also find the qualities of this filter to be ideal for their needs.
The high quality of Baader Planetarium filters permits stacking with no image degradation. For an even less colored view, with noticeably boosted color contrasts, we highly recommend stacking a Moon & Skyglow filter with the Fringe Killer. These two filters compliment each other, and the result is an almost totally neutral view (no coloration).
Image brightness is also very minimally affected, due to the optimized formula of the Moon & Skyglow, along with the superb anti reflection coatings.
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. The Fringe Killer provides a milder more natural filtration, that leaves fast achromats performing much like a classical f/15 achromat. The Fringe Killer delivers what we feel is an ideal combination of improved resolution, contrast and unaltered image brightness, along with a very aesthetically pleasing view.
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
Digital Imagers (CCD, DigiCam, and Webcam) will find the Fringe Killer to be the ultimate mate for their achromatic refractor.
The high transmission and fringe reduction work great for both planetary and deep sky imaging. Baader has also chosen to include their renowned UV/IR Cut coatings as part of the Fringe Killer formula. These coatings maintain very high transmission, with well placed sharp cutoffs in the IR and UV (see the UV/IR Cut filter below, for more detail on these coatings).
Just like all the other Baader Planetarium filters, the Fringe Killer offers their trademark high quality and features. The result is industry leading performance and value.
