Radian Telescopes 2" Triad Ultra Quad-Band Narrowband Filter

  • 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
  • Usable on telescopes up to f/2 speed!
  • Photo Credit: Ross Clark
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  • Regular price $1,075.00

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Radian Telescopes 2" Triad Ultra Quad-Band Narrowband Filter

The Radian Triad 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 5 nm 4 nm 4 nm 4 nm
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.

Below you'll see an incredible image of the Rosette Nebula taken by Jason Guenzel using the Triad Ultra on the super-fast f/2 Celestron RASA telescope! 

Jason Guenzel Nebula with RASA and Triad Ultra

The Triad 2-inch filter is housed in a 7 mm tall ring, with 5 mm height above the threads. The ring wall thickness is between 1.3 and 2.58 mm - depending on production batch. Please double check to make sure this will fit your filter wheel or accessories.


Filter ShapeRound
Filter Thickness3mm
Filter TypeTriad
Free ShippingYes


  • 2-Inch Triad Ultra Quad-Band Filter
  • Filter case
Customer Reviews
4.9 Based on 12 Reviews
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Filter Reviews:
Rod C.
United States United States
Every Astrophotographer Should Have This Filter

This is the best filter I have ever purchased. I use it with a wide field telescope (51 x 250 mm) and Canon EOS Ra DSLR. The images of various nebula's are sharp with great detail even on nights with a fairly bright moon.

Allen G.
United States United States
Triad quad and filter

I have to type fast before my wife sees the debit. The filter is excellent! I shoot from Long Island, close to NYC. The lights come out clear and sharper then with other light pollution filters. I hope I can use it more before my wife murders me. She can, she’s a nurse!

Frederick Z.
United States United States
New to Astrophotography

I just retired and now want to engage in a lifelong ambition - astrophotography. Sebastian at OPT understood what I wanted and guided me in identifying the equipment that would best address my ambitions and grow with me as I grew in experience. OPTs expertise made it easy for me to assemble compatible components to put together a first class astrophotography system. I will continue to do business with OPT!

United States United States
Perfect solution for my shooting situation

Due to free-time constraints and the lack of consistent clear skies, I only shoot with a one shot color CMOS camera. I also have light pollution to contend with from my location. This filter is the perfect solution for my situation. I have been producing excellent images. I have also seen excellent images others have produced using this filter even with a full moon in the sky. It is very expensive for one filter but the cost is not outrageous considering it is actually four filters-in-one.

Game Changer

It's difficult to overstate how significant an impact the Triad Ultra has had on my imaging. I'm not going to lie, it was not an easy purchase; it certainly isn't the cheapest filter out there, but I'm seeing results I would have NEVER been able to get without it. The results on emission nebula is nothing short of stunning, and it's all done without the time or complexity of shooting mono with multiple filters. I'm using it with an ASI294MC, and it's performance with my camera is flawless. The Veil nebula reveals extraordinary color and if far more prominent with far less total exposure time than without the filter. The Eagle Nebula, the North America Nebula, Pelican Nebula, Crescent Nebula, etc are all perfect targets, and will show exceptional detail, depth, and color. As a matter of fact, the data I get with this filter is so good that beyond calibration, stacking, basic color calibration and background extraction, I haven't had to manipulate the images at all. Once the basic routines are complete, I end up with finished products that I am very happy with. If I could give this filter more stars, I would. It's not cheap, but it's been one of my favorite AP purchases.

Jan S.
Czech Republic Czech Republic
The best filter ever

I am using Quadband filter for EAA with Celestron RASA 8 and APO 130mm a its providing excellent results. Now I can do astrophoto even from backyard in big town with extreme light polution.