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Astronomik H-Alpha 12 nm CCD Filter - 31 mm Round - HA12-31

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SKU: ASF-HA12-31

Astronomik H-Alpha 12 nm CCD Filter - 31 mm


  • This photographic filter is presented in a round, 31 mm threaded cell
  • Designed with the highest technical standards to provide the best possible optical performance for deep sky imaging with CCD cameras
  • Permits H-Alpha emissions to pass through while blocking almost the complete rest of the visual spectrum as well as IR
  • The Astronomik H-Alpha Filter has a FWHM of approximately 12 nm
  • Ideal for imaging planetary nebulae and supernova remnants, this filter intercepts all excess light pollution
  • Made in Germany, a country known for their superior quality optics!


More About the Astronomik 31 mm H-Alpha 12 nm CCD Filter


For CCD astrophotography, this Astronomik 31 mm Round H-Alpha 12 nm Filter is the ideal narrowband filter. It has a 12 nm full width at half maximum (FWHM) to allow the use of very fast optics with standard CCD cameras. The f/number application range stretches from 1:2.8 to 1:15. While transmission losses and chromatic distortion can be a problem with other filters, they only become an issue with this filter when extremely bright aperture ratios of 1:2 and more come into play. It should also be noted that the Astronomik 31 mm H-Alpha 12 nm Filter has a transmission of up to 99%. Another advantage of this filter is that finding a guide star is more convenient when used with cameras that have a built-in autoguider.

The Astronomik H-Alpha 12 nm Filter increases the contrast between objects, in this instance between objects with H-Alpha emission lines and the airglow background. In addition, this filter serves as an excellent light pollution filter by completely concealing the emission lines from artificial lighting sources such as those from sodium and mercury-vapor street lamps. Due to the Astronomik 12 nm H-Alpha substrate's high optical quality, you'll see the same razor sharp stars you'd see with a regular telescope.

Like all Astronomik filters, the 31 mm H-Alpha 12 nm is parfocal with all other Astronomik filters, and it is delivered in a high-quality, long-lasting plastic storage case. It completely blocks out all unwanted wavelengths in the visual and IR part of the spectrum. Diffraction limited, your telescope's optical performance will not be compromised. Furthermore, this filter features a very thin substrate and is highly resistant to the effects of scratching, aging, and high humidity.

Transmission Specifications


  • 97+% transmission for the H-Alpha line
  • Blocks nearly the whole remainder of the visual spectrum
  • Blocks unwanted wavelengths in the infrared


Please note this filter must NEVER be used for solar observing or imaging. Doing so will cause permanent damage to your eyes.