ZWO 36mm narrow Filterset OIII/ SII and H-alpha 7 nm

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).

The ZWO H-Alpha filter has a bandpass of 7nm and passes light at 656nm wavelength, light transmission rate comes up to 80%. Best choice of narrowband H-alpha astrophotography 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 !

Hubble look of images can be made by the combination of H-alpha, OIII-CCD and SII-CCD, such as the famous "Pillars of Creation" (M16 Eagle Nebula)Narrowband imaging with SHO set (H-alpha, OIII-CCD and SII-CCD) can be done with the moon up in heavy light pollution, so your equipment is not sitting dormant for several weeks

• 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 natural look

Specification:

FWHM：7±0.5nm
Thickness 2.0 mm (1.25"/31mm/36mm)
Fine-optically polished to ensure accurate 1/4 wavefront  over the both surfaces
80% transmission at H-alpha line 656nm (H-Alpha filter)
80% transmission at SII line 672nm (SII filter)
80% transmission at major OIII line 500nm (OIII filter)