The ZWO H-Alpha filter has a bandpass of 7nm, centred on light at 656nm, with a light transmission of 80%. This is the best choice for narrowband H-alpha astrophotography for high-contrast imaging, revealing rich details of the nebula even in areas with strong light pollution.
Please Note: The 31mm and 36mm filters are unmounted.
The ZWO narrowband S-II 7nm 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 tri-color CCD astrophotography.
The ZWO narrowband O-III 7nm filter is designed for nebula observation, allowing 7nm light centered on a wavelength of 500nm through, corresponding to OIII emission lines and blocking out all other light. Adding the ZWO O-III Narrowband filter to your imaging collection will help you go beyond RGB imaging and will help capture your favorite nebulae in a totally new light, no matter how polluted your skies may be!
- The Hubble palette can be made using the combination of H-alpha, OIII-CCD and SII-CCD, such as the famous “Pillars of Creation” (M16 Eagle Nebula)
- Narrowband imaging with a SHO set (H-alpha, OIII-CCD and SII-CCD) can be done with the moon up in heavy light pollution
- The H-alpha filter is the first narrowband addition to LRGB set for most imagers who blend a black-and-white Ha image into RGB data to enhance structural detail while maintaining a natural look
- Glass Thickness 2.0+/-0.03 mm (1.25”/31mm/36mm)
- 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)
New Narrowband & Old Narrowband Filter Comparison:
New Ha filters are based on new glass base, less reflection( less halo of bright stars).
New SII filters are based on new glass base, less reflection( less halo of bright stars).
New OIII filters are based on same glass base, new coating standard, better block rate of off-band.
Here is a test of ZWO Ha Filters (ASI1600 mono camera, single frame, 300s, DDP in MaximDL) :