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Radian Telescopes 65mm Triad Ultra Quad-Band Narrowband Filter

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  • Regular price $1,995.00

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Accessories Added

  • Shoot in any light polluted area
  • H-Beta, OIII, H-Alpha, and SII Band Passes
  • Works with any color camera including DSLRs
  • Exceptional narrow-band-luminance filter


Radian Telescopes 65mm Triad Ultra Quad-Band Narrowband Filter

The Radian Triad Square filter has now been improved upon! With the Triad Ultra, you now have narrower band-passes, more light pollution reduction, higher contrast, better separation between H-beta and OIII channels, and sensitivity in the Sulfur II emission lines. Like the original Triad filter, the Triad Ultra is designed to work with color cameras but also as a narrow-band-luminance filter for monochrome cameras.

Hydrogen-beta Oxygen III Hydrogen-alpha Sulfur II
FWHM 5nm 4nm 4nm 4nm
Peak Transmission 79% 97% 87% 90%


The Triad Ultra is 100% American made and uses advanced multi-coatings and extreme tolerance glass, to ensure it is always consistent and accurate. Filter thickness is 3 mm.

Since the filter has extremely narrow band passes, telescopes with focal ratios faster than f/4 will move transmission off band. Telescopes with focal ratios between f/2.9 and f/3.9 are compatible with Triad Ultra, with lower transmissions. Between f/2.2 and f/2.8 will have about 0.8nm band-shift.

Choose between the 2-inch threaded, 50 mm unmounted, 65 mm square unmounted, or 52 mm photographic thread filter sizes.



Filter ShapeSquare
Filter Size65mm
Filter Thickness3mm
Filter TypeQuadband


  • Triad Ultra Filter
  • Filter case