With a bandpass of 435nm, cutting frequencies below 500nm wavelength, this yellow longpass colour filter is ideal for visual contrast enhancement of the Moon and planets. Identified by Wratten number W12.
This yellow filter is helpful for suppressing the blue spectrum when viewing using achromatic and half-apochromatic refractors, removing fringing and increasing image sharpness. It's particularly useful for enhancing the cloud belt contrast on Jupiter, and for visual observation of the Lunar and Martian surface.
Features of Baader Colour Filters:
- Largest free opening of all colour filters on the market to elimante any vignetting.
- CNC machined “grip crown” provides excellent handling and comfort.
- Both sides 7-layer AR coating with only 0.25% residual reflection per surface. This is the most antireflective that has ever been undertaken with color filters.
- Planeoptically polished to within 30 seconds of arc for a sharp image at high magnification with non-ageing sealed coating edges.
- Multi-coated for max contrast: no reflections, scatter or dimming.
- The most important criterion for any kind of light filtering is brigthness. Certain spectral ranges at high magnification will only work at the highest light transmittance.
- The long-pass filter in this filter set offers 98% transmission and produces no flare. Unmatched by other brands. This can be seen in comparison with standard colour filters at once – the filter colour radiant downright.
- A wide range of adaptors allow the uses of T-2 photo threads.
- Baader Phantom Group Coating™ developed by Baader Planetarium the coating is a 7-layer broadband coating with extremely low residual reflection. The term “Group” indicates that the respective most effective anti-reflection layer system was calculated for each type of glass of the filter. This means that the anti-reflection layers of different colour filters are different. They are calculated to provide the mximum for the respective filtered colour transmission values. Both sides of the filter are coated with 7-layer AR coating with only 0.25% residual reflection per surface. This is the most that has ever been provided for colour filters. The filter discs are screwed into the blackened aluminium frames and are delivered within a filter. Each filter is designed for multiple applications.
Brand new in the original unopened packaging.