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Astronomik SII 6 nm CCD Filter - 2" - SII6-2

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SKU: ASF-SII6-2

Astronomik SII 6 nm CCD Filter - 2"


  • Mounted in a round 2" threaded cell, this Astronomik SII 6 nm CCD Filter has been designed especially for astro-imaging applications
  • Made with regards to peak technical standards for the optical performance necessary to allow deep sky CCD imaging
  • Ionized sulfur (SII) light is allowed to pass while the complete rest of the visual spectrum as well as IR is cut off
  • FWHM bandwidth of close to 6 nm
  • Ideally equipped for planetary nebulae and supernova remnant imaging
  • Made in Germany, a country recognized for producing high quality optics!


More About the Astronomik 2" SII 6 nm CCD Filter


The Astronomik 2" SII 6 nm CCD Filter is the optimal narrowband filter for CCD astrophotography applications. Features a reduced 6 nm FWHM (full width at half maximum) combined with a typical 96% transmission for an incredible contrast enhancement since all spurious light from wavelengths other than the SII line (672 nm) is cut off from UV up to the IR. This provides a background that is extremely dark. Transmission losses and chromatic distortions, while an issue with other filters, only arise with Astronomik filters when especially bright aperture ratios of 1:2 or more come into play.

CCD filters from Astronomik highlight the contrast between objects. The SII filter highlights the contrast between ionized sulfur (SII) emission line objects and the skyglow background. Plus, this filter also completely obstructs artifical light sources such as mercury (Hg), sodium (Na), and skyglow, making it an excellent filter for use in heavily light polluted conditions. A superior quality substrate allows the Astronomik SII 6 nm CCD Filter to provide the same needle sharp star views you would see with your normal telescope.

All unwanted visible and IR band spectral wavelengths are fully blocked with the Astronomik 2" SII 6 nm CCD Filter. As with all filters from Astronomik, this filter is parfocal with all other Astronomik filters. Diffraction limited, Astronomik SII CCD filters will not compromise the optical efficiency of your telescope. Coatings protect this filter from damage caused by scratching, aging, and high humidity remarkably well. All Astronomik filters come in a long-lasting, high quality plastic filter container.

Transmission Specifications


  • Typical 96% ionized sulfur (SII) line transmission
  • Provides full blockage of undesired light from UV up to IR