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Chroma 31mm OIII 3nm Telescope Filter

SKU : CF-OIII3-31

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  • 31mm OIII 3nm Narrowband Filter
  • Parfocal for systems f/4.0 or slower
  • Transmitted wavefront better than 0.25 waves/inch
  • Made in America
  • Filter sizes up to 2-inch come with a complimentary TPO Filter Case (OS-CF2) to keep your filter safe.

Product Details

  • Please Note:The interference coatings that optical filters are made with are angle-sensitive and shift to the blue with fast focal ratios. This is not a problem for filters 5nm or wider, but the 3nm filters shift enough to compromise transmission at the wavelength line of interest. Chroma has made a set of Ha, OIII and SII 3nm that are optimized for F/3 beams by moving the center wavelength slightly into the red so they will shift slightly to the blue when used in an F/3 beam, thus maximizing transmission at the nominal wavelength. For beams faster than F/3, we recommend using 5nm-wide or wider bands.

    The Chroma 31mm OIII 3nm Narrowband Filter is essential for imaging objects, like nebulae, that are rich in ionized oxygen atoms. These line emission filters work extremely well in heavy light polluted areas and allow you image on nights when the moon is up.

    Chroma manufactures the highest quality astronomy filters with durable, sputtered hard coating using single substrates of the best glass, eliminating the need for laminations. All primary filter coatings are applied on the front surface and anti-reflection coatings on the rear surface to prevent ghosting and to maximize transmission.

    Highly precise and accurate, the passbands of these filters remain spectrally stable and do not drift in response to extreme temperature fluctuations or changes in humidity.

  • specifications

    Bandpass3nm
    Filter ShapeRound
    Filter Thickness1mm
    Filter TypeOIII
    Free ShippingYes
    Size31mm
  • included items

    • 31mm OIII 3nm Narrowband Filter
    • Parfocal for systems f/4.0 or slower
    • Transmitted wavefront better than 0.25 waves/inch
    • Made in America
    • Filter sizes up to 2-inch come with a complimentary TPO Filter Case (OS-CF2) to keep your filter safe.

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Filter Reviews:
    DM
    04/01/2020
    David M.
    Australia Australia
    Chroma O3 filter

    Firstly I live in Australia Delivery was lightning fast 7 days. Great service The Chroma filter is performing flawlessly. I only wish I could post you my first light image, it's pretty amazing, the filter is parfocal with my Astrodons which are in the wheel as well. I couldn't be happier with the goods and OPT