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Astronomik OIII 12 nm CCD Filter - SC Rear Cell - OIIICCD-SCT

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SKU: ASF-OIIICCD-SCT

Astronomik OIII 12 nm CCD Filter - SCT Rear Cell

  • This Astronomik OIII 12 nm CCD Filter comes in a round SCT threaded format and is designed especially for astrophotography purposes
  • Almost 100% transmission in the OIII line
  • 12 nm FWHM bandwidth
  • Optimally suited for imaging the remnants of planetary nebulae and supernovae
  • Multi-layer coatings enable full protection from the damaging effects of scratching, aging, and high humidity
  • Diffraction limited, this filter will not minimize your telescope's optical performance
  • German-designed for supreme optical quality!
  • Works best with minimum 6" aperture telscopes


More About Astronomik OIII 12 nm CCD Filters

This Astronomik OIII CCD Filter is a narrowband emission-line filter, expressly designed for CCD astrophotography, with a 12 nm FWHM. It lets double ionized oxygen from emission nebulae pass through while, at the same time, blocking nearly 100% of the remaining spectral areas where the CCD is more vulnerable. The 12 nm full width at half maximum (FWHM) allows for extremely fast optics to be used with common CCD cameras. For telescopes with apertures over 6" (150 mm), 1:3 to 1:15 is the ideal focal ratio range. It should also be acknowledged that this filter's transmission of up to 99% cannot be achieved by stacking extra narrowband filters. Furthermore, with regards to the dark current of typical CCD cameras, exposures with a CCD cooled to -15°C are limited by the dark current of the CCD, even in large cities with strongly illuminated backgrounds. This led directly to the 12 nm selection. Another benefit of this filter is the increased opportunity for finding guide stars with imagers that have an integrated autoguider.

Emphasizing the contrast between objects in the OIII emission line and the skyglow background, the Astronomik OIII CCD Filter offers complete suppression of emission lines from spurious light sources like mercury (Hg), sodium (Na), and airglow. Loss of transmission and chromatic distortions, which can be a problem with filters available from other manufacturers, are only an issue with Astronomik filters when excessively bright aperture ratios of 1:2 or more are in play. Since this filter has a built-in IR-blocker up to 1150 nm, an extra IR-blocker is not required.

When employing the Astronomik OIII 12 nm CCD Filter in conjunction with an H-Alpha or SII CCD filter, even imaging in an environment with very heavy light pollution will not prevent you from obtaining three-color images of emission line gas nebulae. To accomplish this, you need to capture an image in three different wavelengths, choose each as a color-channel in Photoshop and paste them together as one individual color image. This filter is diffraction limited and will not lower the optical efficiency of your telescope! Astronomik filters arrive with a long-lasting plastic storage box of supreme quality.

Transmission Specifications

  • Transmits more than 99% of both OIII lines
  • Blocks unwanted wavelengths in other parts of the visible spectrum