Baader Dark Blue 435nm Bandpass Filter - 1.25”
This high-quality filter from Baader is comparable to the Wratten #38A Filter in color. It is a bandpass filter with high transmission at 435nm.
More About Baader Color Filters
- Baader Color Filters offer maximum brightness. No reflections, ghosting or stray light.
- Each filter is fine-optically, plane parallel polished to within 30 seconds of arc!
- Professionally coated with 7 layers of MC coatings that result in an image free of false reflections.
- The high quality glass in Baader color filters is only 2 mm thick for easy insertion anywhere in the optical path.
- Stackable filter cells have both male and female threads, allowing you combine filters to suit your needs.
Baader - Not just another colored filter. Baader 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 arc to avoid wedge errors. Finest 7-layer hard multi-coatings on both faces feature 0.25% residual reflections (Baader filters are unique, no other colored filter incorporates anti-reflection multi-coatings). 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 long-pass filters (Red, Orange, and Yellow) peaks at 98%, and efficiencies of the three band-pass 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).