ZWO 1.25 inch Narrowband filter set OIII/SII/H-Alpha
Narrowband filter do not eliminate the effects of light pollution or increase the object’s brightness. In many cases, they increase the contrast between nebula and night sky, not brightening the nebula.
It can reduce the transmission of certain wavelengths of light, specifically those produced by artificial light including mercury vapor. And both high and low pressure sodium vapor lights and the unwanted natural light caused by neutral oxygen emission in our atmosphere (i.e. skyglow).
From 2018, ZWO Made a progress on narrowband filters with new standard, provide better performance.
- Name: ZWO New narrowband 1.25 inch filter
- Size: D=1.25 inch
- Glass Thickness: 1.85 mm
The ZWO H-Alpha filter has a band pass of 7 nm and passes light at 656 nm wavelength, light transmission rate comes up to 80%. Best choice of narrowband H-alpha astro photography filter for high-contrast imaging and revealing rich details of the nebula even in areas with strong light pollution, just prepare to experience the infinite fun with it!
The ZWO narrowband S-II 7 nm filter passes light at 672 nm wavelength with a bandpass of 7 nm 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 astro photography.
The ZWO narrowband O-III 7 nm filter is designed for nebula observation allowing 7 nm bandwidth of light centered on a wavelength of 500 nm through, which corresponds to OIII emission lines, blocking out all other light. Adding the ZWO O-III Narrowband filter to your imaging collection will help you go beyond the RGB imaging and will help capture your favorite nebulas in a totally new light, no matter how polluted your skies may be!
Technical Data of the ZWO 1.25 inch Narrowband filter set OIII/SII/H-Alpha are:
- FWHM：7±0.5 nm
- Glass Thickness 2.0+/-0.03 mm (1.25 inch)
- 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 500 nm (OIII filter )
- Infrared wavelength 700-1100 nm cut-off
- <0.1% transmission of off-band, OD3(Optical Density)