The ZWO SII 7nm 2in filter passes light at 672nm wavelength with a bandpass of 7nm which is designed for nebula observation. It is suitable for visual observation on most emission nebulae, planetary nebulae and supernova remnants, use it with H-alpha and OIII narrowband filters (SHO Set) for tricolor CCD astrophotography.
- Fine-optically polished to ensure accurate 1/4 wavefront over the both surfaces
- About 90% transmission at SII line 672nm (SII filter )
- Infrared wavelength 700-1100nm cut-off
- <0.1% transmission of off-band, OD3(Optical Density)