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
Red long-pass filter 610 nm: Red filter with steep absorption edge. Filters the H-alpha line out of the visible spectrum
- Blue and blue-green light is almost completely blocked, increasing the contrast between the bright zones and dark bands on Jupiter and Saturn
- The most interesting filter for observing the polar caps of Mars
- Optimal filter for daytime observation of all planets
