ZWO 1.25" SII 7nm Narrowband Filter - SII7nm125

The ZWO SII 7nm Narrowband Filter passes light at the 672nm wavelength with a bandpass of 7nm for nebula observation. It is suitable for visual observation on most emission nebulae, planetary nebulae and supernova remnants.  Use this SII (Sulfur II) with H-alpha and Oxygen III narrowband filters (SHO Set) for tricolor CCD astrophotography.

This rendition of the ZWO SII 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.  

How to Use the ZWO SII 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.

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 SII line 672nm

• Infrared wavelength 700-1100nm cut-off

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