ZWO New narrowband 2" filter - 7nm set

ZWO New narrowband 2″ filter

ZWO New Narrowband 2″ Filters – Hα, SII, and OIII for Enhanced Nebula Imaging

The ZWO New Narrowband 2″ Filter Set is designed to increase contrast between nebulae and the night sky without artificially brightening the objects. These filters selectively reduce the transmission of artificial light pollution sources-such as mercury vapor and sodium vapor lamps-and unwanted natural light caused by neutral oxygen in the atmosphere.

Each filter offers a 7nm bandpass with a high transmission rate of about 90% at key wavelengths, making them excellent for detailed narrowband astrophotography and visual observation of emission nebulae, planetary nebulae, and supernova remnants.

Key Features

• Filter Size: 2″ (Thread: M48*0.75 male)

• Thickness: 5mm + 2.5mm thread

• Glass Thickness: 1.85mm

• Bandpass: 7 ± 0.5nm Full Width Half Maximum (FWHM)

• High Transmission: ~90% at Hα (656nm), SII (672nm), and OIII (500nm)

• Infrared Cut-off: 700–1100nm

• Surface Quality: Fine-optically polished for λ/4 wavefront accuracy on both surfaces

• Optical Density: OD3 (off-band blocking <0.1% transmission)

Individual Filter Highlights

• H-alpha 7nm Filter:
  Passes light centered at 656nm, ideal for revealing rich nebular detail in high light pollution areas.

• SII 7nm Filter:
  Passes 672nm wavelength, perfect for visual and CCD imaging of emission and planetary nebulae.

• OIII 7nm Filter:
  Passes 500nm wavelength, designed to isolate oxygen emission lines for dramatic nebula contrast and advanced tricolor (SHO) imaging.

Why Choose ZWO 2″ Narrowband Filters?

• Improve contrast between nebulae and sky background even with heavy light pollution.

• Ideal for narrowband tricolor imaging using SHO filter sets.

• Fine-polished glass ensures minimal image degradation and excellent optical quality.

• Compatible with standard 2-inch filter wheels and imaging setups.

Technical Data

• FWHM?7±0.5nm
• Fine-optically polished to ensure accurate 1/4 wavefront  over the 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 )
• Infrared wavelength 700-1100nm cut-off
• <0.1% transmission of off-band, OD3(Optical Density)

Transmission Curve