H-alpha filter passes light at 656nm wavelength. Best choice of narrowband H-alpha astrophotography filter for high-contrast imaging and revealing rich details of the nebula even in areas with strong light pollution,
Unlike (Ultra) Narrowband filters, this H-alpha filter allows more light to pass through. This makes the stars in the image brighter, which makes focusing easier. In addition, this filter can be used with all aperture ratios. The preshifting required with narrower filters is not necessary.
This filter is particularly interesting for users of colour cameras (which are less sensitive to red than monochrome cameras) when no extreme narrowband filters are to be used and when the red H-alpha component is to be emphasised as much as possible in colour images. At the same time, this filter is a real alternative to a standard R filter in the RGB scheme. It blocks much more of the harmful light pollution and still allows maximum H-alpha signal to pass through for all aperture ratios.
A notable difference to all H-alpha pass filters on the market is the fact that this filter contains a highly efficient UV/IR barrier that completely blocks up to 1400 nm to prevent blurring ("heat noise") caused by defocused light on refractor optics.
The filter offers all the advantages of CMOS-optimised Baader filters:
- Increased contrast, tailored to typical CMOS quantum efficiency and s/n ratio
- Reflex-Blocker™ coatings for maximum insensitivity to retro-reflection from nearby auxiliary optics, even under the most adverse conditions
- Identical filter thickness to existing standards, with the utmost care taken to ensure homofocality
- Blackened edges all around, with filter front indicator in the form of a black outer edge on the telescope side to additionally prevent any reflection from light falling on the filter edge
- Each filter is individually precision-polished and coated, with a sealed coating edge (NOT cut from a larger plate, which would leave the coating edges exposed).
- Life-Coat™: even harder coatings to enable an age-resistant coating with an unlimited service life – even in the most adverse environments
