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Astronomik H-Alpha 6 nm CCD Filter - SCT Rear Cell - HA6-SCT

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SKU: ASF-HA6-SCT

Astronomik 6 nm H-Alpha Filter - SCT Rear Cell


  • This Astronomik H-Alpha CCD Filter is mounted in a round SC Rear Cell format
  • Designed with the highest technical standards in mind to enable the superb optical performance desired for imaging deep sky objects
  • Lets H-Alpha emissions pass through while, at the same time, obstructs almost the entire balance of the visual spectrum including IR
  • FWHM of nearly 6 nm
  • Blocks all unwanted light pollution and is optimal for planetary nebulae and supernova remnant imaging
  • Made in Germany, a country noted for producing superior quality optics!


For CCD imaging with instruments as fast as f/3.5, the Astronomik H-Alpha 6 nm Filter is an excellent narrow emission-line filter. Not applicable for visual or solar operations. This filter allows h-alpha light from emission nebulae to pass through to your sensor while obstructing the remainder of the spectrum entirely.

With a 6 nm full width at half maximum (FWHM), this filter is optimized to display maximum contrast between objects in the h-alpha spectral area, such as emission nebulae, and the background skyglow. While the 12 nm provides functionality analagous to the 6 nm, the latter offers higher contrast gain due to its reduced FWHM. To compromise, some background stars will appear dimmer or be completely eradicated from the final image. This can be avoided simply by using both the 6 nm and 12 nm filters at the same time, allowing for maximum contrast in h-alpha objects while maintaining the visibility of background stars in the resulting image.

Because the Astronomik 6 nm H-Alpha CCD Filter offers complete suppression of mercury (Hg) and sodium (Na) emissions lines, the primary causes of light pollution, it makes for a fine solution when working in light-polluted surroundings.

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