ZWO SII 7NM FILTER 36MM

Narrowband filters do not eliminate the effects of light pollution or increase the object’s brightness, but rather increase the contrast between nebula and night sky. 

They 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 'Hubble look' can be produced with the combination of H-alpha, OIII-CCD and SII-CCD, as in 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

TECHNICAL PARAMETERS:

Name: ZWO New narrowband 36mm filter

Size: D=36mm

Thickness: 2mm

The ZWO narrowband S-II 7nm filter passes light at a 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 for tricolor CCD astrophotography.

CORRECT ORIENTATION

Note: example uses 1.25" filter

Technical Data

• FWHM：7±0.5nm
• 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 SII line 672nm (SII filter )
• Infrared wavelength 700-1100nm cut-off
• <0.1% transmission of off-band, OD3(Optical Density)

TRANSMISSION CURVE

NEW NARROWBAND & OLD NARROWBAND FILTER:

New SII filter is on a new glass base, with less reflection (less halo of bright stars).