Optolong SHO Narrowband Deep Sky Imaging Filters

Optolong SHO Narrowband Deep Sky Imaging Filters

  (2 Reviews)
✓ 2 year warranty


2x in stock shipped 1-2 working days

About this product

Model:  opt_sho_36mm

Latest Version - Higher contrast and coating enhancements.

Narrowband filter set including SII (S) 6.5nm, Ha (H) 7nm and OIII (O) 6.5nm filters.

Narrowband imaging can be done with the moon up or in heavy light pollution so you can make the most of every clear night.

Data from each narrowband filter can be combined to create a final colour image, a common combination is HOO using H-alpha for the red and OIII for the green and blue channels. It can also be useful to use H-alpha data blended into an RGB data set to enhance the contrast and structural detail whilst maintaining a natural look.

IMPORTANT: Filters manufactured by Optolong are NOT designed for observing or photographing the Sun. DO NOT use Optolong filters to observe or photograph the Sun. If you do it will result in permanent eye damage! 


  • 80% transmission at passband / Precision off-band blocking
  • Infrared wavelength 700-1100nm blocked
  • 0.1% transmission of off-band, specifically the major emission lines of artificial light pollution (i.e. Na 589nm, Hg 435nm and 578nm)

  • Suitable for use with mono CCD and CMOS cameras
  • 1.25" / 2" mounted or 31mm / 36mm unmounted sizes.
  • Supplied in a protective plastic case with EVA foam lining
  • 2mm Thick Schott Glass
  • Fine-optically polished on both sides - ensures accurate λ/4 wavefront and <30 seconds parallelism over the both surfaces

Transmission Chart

Red Line: H-alpha, 7nm centred at 656.3nm.

Blue Line: SII, 6.5nm centred at 671.6nm.

Green Line: OIII, 6.5nm centred at 500.7nm

Technical Data

  • Schott substrate material
  • Thickness 2.0 mm
  • Surface Quality: 60/40 (Refer to MIL-O-13830)
  • Fine-optically polished to ensure accurate 1/4 wavefront and <30 seconds parallelism over the both surfaces
  • 95% transmission at passband
  • Infrared wavelength 700-1100nm cut-off

  • Precision off-band blocking

Coating Parameter

  • Multi-layers anti-reflection coating
  • Non-cementing optical substrate coating
  • Electron-beam gun evaporation with Ion-assisted deposition coating technology for durability and resistance to scratching, as well as stability on CWL (central wavelength) no deviation affected by temperature change
  • Planetary rotation system offers precision and homogeneity of coatings ensuring high value on transmission of pass-band and Optical density of off-band

Filter Cell

  • Ultra-thin filter cell minimise vignetting by maximise possible clear aperture (clear aperture is 26mm for 1.25”; 45mm for 2”)
  • Aerometal Material | Precise CNC Machining | Sand Blasting Process | Black Anodised Finish | Extinction Treatment to Prevent Reflection | Laser Engraving No Fading

Sample Images


Customer reviews

Average Rating (2 Reviews):  
Write a Review and share your opinions!

Rating (max 5):  
Great filters, especially Ha
17 May 2022  | 

I ordered the 2" version of the SHO Narrowband filter set. I have just run few tests using the ASI6200mm camera and this filter set. The Ha filter produces beautiful, pin-sharp images. For some reasons the SII filter shows slight vignetting when stretching the image in PhotoShop. Not really a big problem. I have not really tried the OIII filter properly yet.

Rating (max 5):  
Getting good contrast with c8 and hyperstar
08 August 2021  | 

Work great very pleased


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