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Astronomik 6nm H-Alpha Astrophotography Filter in Excellent Condition!  Very Clean!

Photographic Astronomik Narrowband-Emissionline filter H-alpha-CCD with 6nm FWHM and MFR Coating

This H-alpha Filter is suitable for imaging of Hydrogen nebulas from observation sites with light pollution and from dark sites as well. The contrast between an object glowing at 656nm and the background is increased enormous!

Due to the combination of the narrow bandwidth of 6nm and the high transmission of typically 96% the filter gives you an enormous contrast boost, as all unwanted light from other wavelengths than 656nm is blocked form UV up to the IR. This results in an extremly dark background.

The FWHM of 6nm is matched to give you optimal performance with CCD and CMOS sensors with a very low dark current! The 6nm filter is the best choice if you are observing from a heavily light polluted site or if you are imaging faint objects in starcrowded regions of the milkyway.

Due to the new MFR coating technique you may use one single filter on all instruments up to f/4 without a significant reduction in performance.


The Astronomik H-alpha filter MUST NOT BE USED for solar observation!


Technical data of the filter:

  • Guaranteed Transmission of more than 90% at the H-alpha Line (656 nm)
  • Typical Transmission of 96% at the H-alpha Line (656 nm)
  • Full-Width-Half Maximum (FWHM): 6nm
  • perfect blocking of unwanted light from UV up to the IR
  • parfokal with all Astronomik filters
  • MFR Coating technique: Usable with all optics up to f/4
  • Thickness of 1mm
  • Not sensitive to moisture, scratch resistant, not aging
  • opticaly polished substrate, striae-free and free of residual stresses
  • High quality storage box

Imaging with Narrowband-Emissionline Filters

If you have to observe from light polluted sites (like most of us...), imaging with Narrowband-Emissionline filters is the best way to take great images, as all kind of light pollution can be blocked very effective! Normaly an H-alpha filter should be your first step into this amazing field of astrophotography! With an Narrowband H-alpha filter you will be able to take deep and contrasty images even with very heavy light pollution or with the full moon high up in the sky!

Operation of the filter:

The filter blocks all unwanted light from artifical light-pollution, natural airglow and moonlight. Especially light from High- and Low-Pressure Sodium and mercury lights and all lines of natural airglow are 100% blocked. The filter increases the contrast between the sky-background and objects glowing at the xx line at xy nm.

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