Baader Premium Eyepiece Filter: Dark Blue, 435nm Bandpass - 1.25" # FCFDB-1 2458
Not just another colored filter! Finally, a set of serious tools for the planetary observer. Baader Planetarium's Premium Colored Filters bring a new level of quality and performance to planetary contrast enhancement.
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). The coatings are also different for each of the filters, in order to match the coating performance to the filter curve of each color. This maximizes the transmission and minimizes 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. 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. For actual spectral traces, see Color Filter Transmission Curves.
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).
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.
Manufacturer part #: FCFDB-1 or 2458302