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ZWO 31 mm H-alpha SII OIII 7nm Filter Set

SKU : ZWO-NBSET7-31MM

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  • FWHM:7 plus or minus 0.5nm.
  • Glass Thickness 1.9+/-0.03 mm.
  • Fine-optically polished to ensure accurate 1/4 wavefront over both surfaces.
  • About 90% transmission at H-alpha line 656nm (H-Alpha filter).
  • About 90% transmission at SII line 672nm (SII filter).
  • About 90% transmission at major OIII line 500nm (OIII filter).

Transmission Curve of the ZWO 31 mm Filter Set

ZWO 31 mm Filter Set Transmission Curve Graph

Product Details

  • The ZWO 31 mm H-alpha SII OIII 7nm Filter Set allows only Hydrogen, Oxygen, and Sulfur emissions to be photographed. These filters will enhance contrast for these wavelengths and block most wavelengths produced by city lights. Narrowband filters will reduce the transmission of most wavelengths an only allow certain ones narrow bands to pass. 

    Technical Data of the ZWO 31 mm Filter Set

  • specifications

    Bandpass7nm
    Filter Thickness1.9 mm
    Filter TypeH Alpha
    Filter TypeOIII
    Filter TypeSII
    Free ShippingYes
    ShapeRound
    Size31mm
  • included items

    • H-Alpha filter.
    • SII Filter.
    • OIII Filter.
    • Case x3.

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