With all substrates fine optically polished. These filters by far supersede the mediocre quality of common `flame polished` colour filters. Fine optical polish and 2mm thickness allows these filters to be inserted anywhere into the optical path without introducing astigmatism or other defects. For instance they can be used in front of a binocular viewer without degrading the image in any way. Substrates are free of striae and plane parallel polished to within 30 seconds of arc. This eliminates any double images or ghosting due to wedge errors in the glass. PCG multi-coating.
The set comprises three longpass and three genuine bandpass filters, which act similar to a nebula filter, so that only a small portion of the visual spectrum is transmitted to emphasise certain planetary surface detail.
Transmission efficiencies for the three longpass-filters (Yellow, orange and red) peaks at 98 %, while the efficiency for the three bandpass-filters peaks at almost 70 percent – unheard of for a simple coloured glass-filter!
All filters have standard 31.7mm or 48mm eyepiece filter threads, tested and optimised to fit almost all eyepieces on the market. Each filter cell has a male as well as a female thread to allow stacking for narrower passbands or to combine with our UV/IR Cut-filter. The combination of the red RG 610 (# 2458307) and IR-Cut-filter (# 2459207) for instance results in an extremely narrow H-alpha passband-filter – at an incredibly cheap price.
The filter cell features the largest clear aperture of any colour filter on the market – for complete freedom from vignetting at any focal length. The front `crown` incorporates milled notches, which makes handling and threading the filter an easy operation in the dark.
All surfaces are treated with a 7-layer Multi-Coating, featuring a mere 0.25 % residual reflection. It is the most sophisticated coating ever applied onto amateur colour filters, resulting in a filter free of any false reflections under any incident angle of light. The 7-layer MC coatings not only provide a brighter image – most important of all – they also prevent the softening effect of scattered light. Scattered light reduces subtle detail when observing planets.
Colour filters are often identified with a Kodak Wratten number (W-point). Baader colour filter were collected by astronomical experience and correspond to the respective wavelength range of the following filters by 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
Dark Blue Filter
- 435 nm Dark blue bandpass filter. Filter for visual and photographic planetary observations
- Better detection of phase design of Venus
- The violet clearing on Mars can be seen better
- To observe the great Red Spot on Jupiter, enhances the contrast between the belts and zones on Saturn
Light Blue Filter
- 470nm Light blue bandpass filter. Filter for visual and photographic planetary observations
- To observe high clouds on Mars, enhances the contrast of hazes on terminator of Mars (Violet Klarglasing)
- Displays reddish structures darker, therefore the ideal filter for observing the large red spot on Jupiter - also shows details in Saturn Ring better
- To monitor structures in the atmosphere of Venus, also highlights the fine details in gas tails of comets
- Green bandpass filter 500nm. Provides the sharpest images with achromatic and semi-apo refractors (eg double star observations)
- Improves the visibility of CO² hoarfrost and ground fog on Mars
- Increases contrast between red and blue regions in Jupiter and Saturn
- Displays on the moon the best contrast in radiation craters Tyco, Copernicus and Kepler
- 495nm Yellow long pass filter. Suppresses the secondary spectrum (blue portion) with achromatic and semi-apo refractors (image sharpness is increased)
- The contrasts of lunar and Martian surface increased
- The filter also enhances the contrast between the bands and zones of Jupiter clouds
- With larger instruments from 8 "opening can be seen on Saturn Details.
- 570nm Orangener long pass filter. Contrast enhancement in lunar and planetary observations at dusk
- Improves the detection of dark areas on Mars and penetrates the haze of the Martian atmosphere
- Shows more details in the cloud bands of Jupiter and Saturn
- ideally suited to daily observations of the moon, Mercury and Venus
- 610nm Red long-pass filter. Red filter with a steep absorption edge. Filters the H-alpha line from the visible spectrum from
- Blue and blue-green light is almost completely blocked, thereby increase contrasts between the light areas and the dark bands on Jupiter and Saturn
- The most interesting filters for observing the polar caps of Mars
- An optimum filter for daily observation of all planets