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Astronomik OIII 12 nm CCD Filter - 36 mm Round - OIIICCD-36

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SKU: ASF-OIIICCD-36

Astronomik OIII 12 nm CCD Filter - 36 mm


  • This Astronomik OIII 12 nm CCD Filter is presented in a round, 36 mm cell and is made especially for astro-imaging
  • Close to 100% transmission in the OIII line
  • 12 nm FWHM bandwidth
  • This filter is optimal for imaging planetary nebulae and vestiges of supernovae
  • The coatings on this filter offer remarkable protection from defects resulting from scratching, aging, and high humidity
  • Diffraction limited, this filter will maintain the optical efficiency of your telescope
  • Made in Germany, a country with a reputation for producing high quality optics
  • Optimal for telescopes sporting an aperture of at least 6"


More About the Astronomik 36 mm OIII 12 nm CCD Filter


A narrowband emission-line filter designed specifically for CCD astrophotography, the Astronomik OIII CCD Filter simultaneously allows the double ionized oxygen of gas nebulae to pass through while blocking almost the entire remainder of the spectrum in the more CCD sensitive parts. The 12 nm full width at half maximum (FWHM) enables the use of very fast optics with typical CCD cameras. With telescopes that have apertures over 6" (150 mm), the ideal focal ratio range for this filter is 1:3 to 1:15. It should also be noted that this filter features a transmission of up to 99%, a number that cannot be reached simply by stacking more narrowband filters. Regarding the dark current of common CCD imagers, CCD-cooled exposures to -15°C are restricted by the CCD's dark current, even in large, brightly lit metropolitan areas. This led to the selection of 12 nm FWHM. An additional benefit of this filter is the increased availability of guiding stars for cameras featuring a built-in autoguider.

The contrast between OIII emission line objects and those in the background sky is greatly enhanced by this Astronomik OIII CCD Filter. It completely cuts off artificial light emissions from mercury (Hg), sodium (Na), and skyglow. Unlike with filters from other manufacturers, the Astronomik 12 nm OIII CCD Filter won't have any transmission loss or chromatic distortions unless extremely bright aperture ratios of 1:2 or more are involved. Because this filter incorporates an IR-blocker up to 1150 nm, an additional IR blocking filter is not necessary.

Using a combination of this Astronomik OIII 12 nm CCD Filter with an H-alpha or SII CCD filter enables the creation of three-color images of emission line objects (gas nebulae), even under severely light-polluted conditions. To do this, you'll need to take the image in three different wavelengths and combine them into a single image in Photoshop by selecting each as a separate color-channel and pasting them together. Diffraction limited, this filter will not cause any reduction in the optical performance of your telescope! All Astronomik filters are delivered with a durable plastic filter box of superior quality.

Transmission Specifications


  • 99+% transmission for both of the OIII lines
  • Blocks undesired wavelengths in other parts of the visual spectrum