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Astronomik OIII 12 nm CCD Filter - 42 mm Round - OIIICCD-42

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Astronomik 42 mm OIII 12 nm CCD Filter

  • Astronomik OIII 12 nm CCD Filter in a round 42 mm format designed specifically for astrophotography purposes
  • Nearly 100% transmission in the OIII line
  • FWHM bandwidth of approximately 12 nm
  • Optimally suited for imaging planetary nebulae and supernova remnants
  • Multi-layer coatings protect this filter incredibly well from the effects of scratching, aging, and high humidity
  • Diffraction limited, this filter will not reduce the optical performance of your telescope
  • Made in Germany, a country renowned for producing optics of superior quality!
  • Ideally equipped for telescopes with apertures measuring 6" and higher

More About Astronomik OIII 12 nm CCD Filters

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.

Highlighting the contrast between objects in the OIII emission line and objects in the skyglow background, the Astronomik OIII CCD Filter completely eliminates artificial light sources such as mercury (Hg) and sodium (Na) from street lamps. With the exception of extremely bright aperture ratios of 1:2 or more, transmission losses and chromatic distortions are not a problem, unlike with filters from other brands. Since this filter has an integrated IR-blocker up to 1150 nm, you won't need a supplementary IR-blocker to go with it.

Employing a combination of this filter with an H-alpha or SII CCD filter allows for the production of three-color images of emission line gas nebulae, despite any heavily light-polluted environments. For this, you would need to utilize Photoshop to combine an image taken in three different wavelengths by choosing each as a separate color-channel and pasting them together. The Astronomik OIII CCD Filter is diffraction limited to preserve the optical performance of your telescope. Astronomik filters arrive with a long-lasting, high quality plastic storage container.

Transmission Specifications

  • Over 99% transmission for both OIII lines
  • Blocks unnecessary wavelengths from other parts of the visual spectrum