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Astronomik OIII Visual Filter - SC Rear Cell - OIII-SCT

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SKU: ASF-OIII-SCT

Astronomik OIII Visual Filter - SC Rear Cell


  • This round, SCT Rear Cell mounted Visual Filter from Astronomik is optimally suited for visual observation of gas and planetary nebulae
  • Near 100% OIII line transmission
  • 15 nm approx. FWHM bandwidth
  • Coatings provide exceptional protection against damage caused by scratching, aging, and humidity
  • This filter is diffraction limited and therefore will not compromise your telescope's optical performance
  • Astronomik OIII filters are best equipped for 6" aperture telescopes or more
  • Made in Germany, a country known for producing high quality optics!


More About the Astronomik SC Rear Cell OIII Visual Filter


Since the beginning, Astronomik has designed their OIII filters specifically for visual observation of gaseious and planetary nebulae. Both OIII lines have extremely narrow pass bands for strong contrast gain to these lines even under the most favorable observing conditions. Frequently, the Astronomik OIII Filter will be the component necessary to enable an object such as faint vestiges of supernovae or planetary nebulae to be seen at all! This filter can therefore extend the view of scattered objects, broadly speaking, to the eyepiece's entire visual field of view, and is not limited only to the center.

Ideally, this filter should be used with telescopes featuring apertures of 6" (150 mm) or more since a sufficient amount of light is required to use it. Smaller telescopes do not accumulate enough light for any meaningful astronomical output. In fact, for 10" (250 mm) or larger aperture telescopes, many veteran deep sky observers favor using the OIII filter over the more versatile UHC filter. The incredible optical quality of the Astronomik OIII Filter substrate will enable you to see pinpoint stars identical to those you would see with your regular telescope.

Astronomik OIII Visual Filters have almost 100% transmission in each OIII line. Optically polished, the substrate provides excellent carrier material. Like all filters from Astronomik, this filter is parfocal with all other Astronomik filters. Comes with a long-lasting plastic storage container of superb quality.

Transmission Specifications


  • More than 99% transmission for both OIII lines
  • Blocks superfluous wavelengths in other visible spectrum areas