Baader Planetarium 1.25" Dark Blue Colour Filter - 435nm Bandpass
Not just another coloured filter. Finally, a set of serious tools for the planetary observer. Baader Planetarium's Premium Coloured Filters bring a new level of quality and performance to planetary contrast enhancement. Available singly, or as a full set of 6 filters.
Freedom from Ghost images, even when stacked. Striae-free substrates are polished parallel to 30 seconds of to avoid wedge errors. Finest 7-layer hard multicoatings on both faces feature 0.25% residual reflections (Baader filters are unique, no other colored filter incorporates anti-reflection multicoatings).
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. Filters may be stacked without image degradation or ghosting, in order to provide even narrower passbands. Or, combine with any of the other Baader filters for interesting 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).
With the new 2 inch size, only one filter is needed for binoviewing. Only Baader colored filters have the optical quality necessary for use this far ahead of the focal plane.