About this product
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.
Warning - Optolong filters are not designed to be used for solar observation. Do not look at the sun through this filter as it will cause permanent eye damage.
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
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



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