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Astronomik SII 12 nm CCD Filter - 50 mm Square - SII-50SQ

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SKU: ASF-SII-50SQ

Astronomik SII 12 nm CCD Filter - 50x50 mm


  • Astronomik SII CCD Filters are made for CCD photography with this particular model coming in a 50 mm square format
  • By designing the SII 12 nm CCD Filter with regards to peak technical standards, Astronomik has created a filter that provides the optical performance you seek for deep sky CCD imaging applications
  • Ionized sulfur (SII) light is allowed to be transmitted while the whole remainder of the visual spectrum plus IR is blocked
  • This Astronomik SII CCD Filter has an FWHM of approximately 12 nm
  • Best-suited for imaging planetary nebulae and supernovae remnants
  • German-designed for supreme quality optics!


More About the Astronomik 50 mm Square SII 12 nm CCD Filter


This 50 mm Square SII CCD Filter from Astronomik is the ultimate narrowband imaging filter for performing CCD astrophotography. Its 12 nm full width at half maximum (FWHM) is optimal for typical CCD cameras, allowing the use of exceptionally fast optics. The f/number application range spans from 1:2.8 to 1:15. Astronomik filters only experience transmission losses and chromatic distortions when severely bright aperture ratios of 1:2 or more are involved, whereas with other filters they arise with more frequency. A further benefit of 12 nm filters is the enhanced availability of guide stars for cameras featuring a built-in autoguider. Up to 99% transmission.

Astronomik's CCD filters enhance the contrast between objects. The SII filter enhances contrast between SII emission line objects and the background sky while offering total suppression of mercury (Hg) and sodium (Na) and other artificial light emissions, as well as skyglow, making it an excellent filter to use in light polluted conditions. Because of the high quality of the Astronomik SII 12 nm CCD substrate, you'll see the same razor sharp stars as you would from your regular telescope.

All unwanted visible and IR spectral band wavelengths are fully obstructed with this 50x50 mm SII 12 nm CCD Filter from Astronomik. Like all Astronomik filters, the 50 mm Square SII 12 nm CCD Filter is parfocal with all other Astronomik filters. It has an ultra thin substrate and is diffraction limited to preserve your telescope's optical performance. Coatings offer total protection from scratching as well as the effects of aging and high humidity. All Astronomik filters arrive in a long-lasting, supreme quality plastic filter container.

Transmission Specifications


  • Over 97% transmission of the ionized sulfur (SII) line
  • Blocks nearly the entire rest of the visible spectrum
  • Obstructs undesired wavelengths in the infrared