About this product
Latest Version - Higher contrast and coating enhancements.
The Optolong SII 6.5nm filter allows 6.5nm bandwidth of light centered on a wavelength of 672nm through. This filter does an excellent job of blocking out other wavelengths of light specifically artificial sources of light pollution including mercury vapour, high and low pressure sodium vapour lights and unwanted natural light caused by neutral oxygen emission in our atmosphere (skyglow).
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.
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
- 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
- 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
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