These Baader colour filters are carefully prepared for amateur astronomical use for contrast enhancement of lunar and planetary observations. Colour filters are often identified with a Kodak Wratten (W) number. Baader colour filters were developed and manufactured to correspond to the respective wavelength range following the Wratten nomenclature:
- Baader-red filter ≅ W25,
- Baader-Orange filter ≅ W21,
- Baader-yellow filter≅ W12,
- Baader-green filter≅ W58,
- Baader-light blue filter ≅ W80A,
- Baader-dark blue filter≅ W38A
Below is the transmission curve of the Baader colour filters.
The filters are screwed into the filter thread of eyepiece barrels or in planetary imaging camera nosepieces (e.g. Skyris). A thread at either end of the filter allows the filters to be combined (i.e. stacked) with each other or with other filters (for example with the Baader UV / IR infrared cut filter).
The glass are co-planar fine optically polished. These filters exceed the quality of the usual “raw polished” (hot flamed) coloured glass filters. As they are fine optically polished, these filters can be at any point in the mean path – far ahead of the focal point (for example, in front of a binocular approach!) without causing defects (astigmastism) or to degrade the image otherwise in any way! The parallelism of the optical surfaces is excellent to within 30 arcseconds meaning that “double images” are not present. The transmission curve for each filter colour is also supplied.
|Red 610nm longpass filter with steep absorption edge.|| |
|Orange 570nm longpass filter.|
|Yellow 435nm Longpass filter.|
|Green 500nm bandpass filter.|
|Light Blue 470nm bandpass filter.|
|Dark Blue 435nm bandpass filter.|
- 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 â€“ 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.
- The combination of our infraread (IR) cut filter 1¼” and the RG 610 red filter results as an extremely narrow-band H-α pass filter for the CCD photography of red emission nebulae – at a ridcidulously low price!
- A wide range of adaptors allow the uses of T-2 photo threads (See: Baader Astro T-2 System™).
- 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.
|TRANSMISSION RANGE||multiple bands (see spectral image)|
|FILTER THICKNESS (WITHOUT CELL)||2 mm|
|AR-COATING||Phantom Coating® Group, planeoptically polished|
|FILTER SIZE||1 25 inch / 2 inch|
|FILTER USAGE||Color, Planetary|
|FILTER MOUNTED||Mounted (LPFC 6mm)|
|TYPE OF FILTER||Bandpass, Longpass|
|SINGLE OR SET?||Filter-Set|