Baader 2" Blue 470 nm Bandpass Eyepiece Filter

Freedom from Ghost images, even when stacked. The substrates of this Baader 2" filter are free of striae and polished parallel to 30 seconds in order to avoid wedge errors. It features the finest hard 7-layer multi-coatings on each face with 0.25% residual reflections. Baader filters are special in this regard as all competing filters are without anti-reflection multi-coatings. Futhermore, the coatings differ for each filter so that they match the coating performance to each color's filter curve to increase transmission while decreasing reflections.

Extremely High Transmissions result in maximum contrast and isolation of planetary details, even with smaller telescopes.  Efficiencies of the three longpass filters (Red, Orange, and Yellow) peaks at 98%, and efficiencies of the three bandpass filters (Green, Blue, Dark Blue) achieve 70%. 

Carefully designed spectral characteristics. Baader 2" color filters are stackable without image deterioration or ghosting, for even more narrow passbands. You can also combine them with other Baader filters for many potential possibilities.

No reduction in sharpness, even at high magnifications or when using the filter far ahead of the focal plane (ie, digital imaging, or in front of a diagonal or binoviewer).