ZWO 36 mm H-alpha SII OIII 7nm Filter Set

  • Observe increased contrast between nebula and the night sky, without brightening the nebula. 
  • Each polished to reach an accurate one-fourth wave.
  • Multi-layered anti-reflection coatings.
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  • Regular price $479.00

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ZWO 36 mm H-alpha SII OIII 7nm Filter Set

The ZWO 36 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 and only allow certain ones narrow bands to pass.

Technical Data of the ZWO 36 mm Filter Set

  • FWHM: 7±0.5nm.
  • Glass Thickness 2.0+/-0.03 mm  (1.25 inches/ 31 mm/ 36 mm).
  • Fine-optically polished to ensure accurate 1/4 wavefront over the both surfaces.
  • About 90% transmission at H-alpha line 656 nm (H-Alpha filter).
  • About 90% transmission at SII line 672 nm (SII filter).
  • About 90% transmission at major OIII line 500nm (OIII filter).
  • Infrared wavelength 700-1100 nm cut-off.
  • <0.1% transmission of off-band, OD3 (Optical Density).

Transmission Curve

Transmission Curve Graph


Filter Thickness1.9 mm
Filter TypeH Alpha
Filter TypeOIII
Filter TypeSII
Free ShippingYes


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