ZWO OIII 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 O-III 7nm filter is designed for nebula observation allowing 7nm bandwidth of light centered on a wavelength of 500nm through, which corresponds to OIII emission lines, blocking out all other light.

CORRECT ORIENTATION

Note: example uses 1.25" filter 

1. Lay the filter down flat;
2. Hold a pen over the top;
3. If you can see two shadows, this side has anti-reflective coating, and should face to the camera.

4. If you can only see one shadow, this side has multilayer coating, and should face the telescope.

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 major OIII line 500nm (OIII filter)
• Infrared wavelength 700-1100nm cut-off
• <0.1% transmission of off-band, OD3(Optical Density)

TRANSMISSION CURVE

NEW NARROWBAND & OLD NARROWBAND FILTER:

New OIII filter is on the same glass base, with new coating standard and better block rate of off-band.