ZWO 1.25" H-Alpha 7nm Narrowband Filter - Ha7nm125

The ZWO H-Alpha filter has a bandpass of 7nm and passes light at the 656nm wavelength, with a light transmission rate of up to 80%. This is the best choice for a narrowband H-alpha astrophotography filter if you are doing high-contrast imaging and want to reveal rich details of the nebula even in areas with strong light pollution.

This rendition of the ZWO Ha 7nm Filter is housed in a 1.25" threaded metal cell and can be used in 1.25" filter wheels or the ZWO 2" filter drawer with a 2" to 1.25" filter adapter installed.  

Do not use this filter for viewing or photographing that Sun; eye and/or equipment damage could occur.

How to Use the ZWO Hydrogen-Alpha (Ha) 7nm 1.25" Filter...

• A Hubble look 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 in the sky so your equipment is not sitting dormant until the next new moon.

• An H-alpha filter is the first narrowband addition to an LRGB set for most imagers who want to blend a black-and-white Ha image into RGB data to enhance structural detail while maintaining natural look.

Specifications

• Size: 1.25″

• Thickness: 5.5mm + 2.5mm(thread)

• Glass thickness: 1.85mm

• Thread: M28.5*0.6 male thread

• 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

• Infrared wavelength 700-1100nm cut-off

• <0.1% transmission of off-band, OD3 (Optical Density)