Baader colour filters are carefully manufactured for amateur astronomical use. The glass is finely polished to be plane-parallel. These filters far exceed the quality of the usual "roughly polished" (= hot-blazed) colour glass filters.
Thanks to their fine optical polish, these filters can be used at any point in the beam path – well in front of the focal point – (e.g. in front of a binocular attachment!) without causing optical errors (astigmatism) or otherwise impairing the image in any way!
Further special features of Baader filters:
- Elaborate frame with the largest possible free opening to prevent vignetting
- CNC-milled "crown grip" – offers excellent handling comfort
- 7-layer anti-reflection coating on both sides with only 0.25% residual reflection per surface
Green Bandpass Filter 500nm: Provides the sharpest images with achromatic and semi-apochromatic refractor lenses (e.g. double star observations)
- Improves the visibility of CO² frost and ground fog on Mars
- Increases the contrast between red and blue regions on Jupiter and Saturn
- Shows the best contrast on the moon in the Tyco, Copernicus and Kepler ray craters
