The Telescope Authority
Since 1947

View Shopping Cart

Your Cart is Empty

Radian Triad Ultra Narrowband Filter 2"


- Read
  • Free Shipping

  • In Stock

Add to Wishlist

Got questions? Click for live chat

  • Shoot in any light polluted area
  • H-beta, OIII, H-alpha, and SII Band Passes
  • Works with any camera including DSLRs
  • Exceptional narrowband & luminance filter
  • If your telescope is f/3 or faster, you need the fast telescopes version here
  • Photo Credit: Ross Clark

Product Details

  • Unmatched Multi-Narrowband Performance

    The Triad Ultra filter stands alone in its class as a filter with four ultra-narrow bandpasses that cover Hydrogen alpha, Hydrogen beta, Sulfur II, and Oxygen III wavelengths - the four most common wavelengths for narrowband astrophotography. As a multi-narrowband filter, the Triad Ultra is designed to photograph emission nebulae, planetary nebulae, and supernova remnants, and excels at doing so from light pollution. However, we recommend you try it from dark skies as well - the narrow bandpasses will give you tighter stars and more pronounced nebulosity.

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

    Use Case for Monochrome Cameras

    You might think that the Triad Ultra is only designed for color cameras, but it actually works great on monochrome cameras too! A traditional luminance filter has a broad bandpass that lets light in from around 400 to 700nm. This works well for broadband imaging of galaxies and reflection nebulae, for example, but will be affected heavily by light pollution with such a broad bandpass. With the Triad Ultra, you can gather luminance data in all four major wavelengths while simultaneously cutting out light pollution and you get the added benefit of keeping the stars tight and small. Think of it as the ultimate luminance filter for your monochrome camera!

    American Made

    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 3mm.

    Below you'll see an incredible image of the Rosette Nebula taken by Jason Guenzel using the Triad Ultra:

    Jason Guenzel Nebula with RASA and Triad Ultra

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

    Shop the full Radian Triad Filter Lineup

  • specifications

    Filter ShapeRound
    Filter Thickness3mm
    Filter TypeLight Pollution/City Light Suppression
    Filter TypeTriad
    Free ShippingYes
  • included items

    • 2-Inch Triad Ultra Quad-Band Filter
    • Filter case

Product Reviews

Customer Reviews
4.8 Based on 28 Reviews
5 ★
4 ★
3 ★
2 ★
1 ★
Customer Photos
Write a Review Ask a Question

Thank you for submitting a review!

Your input is very much appreciated. Share it with your friends so they can enjoy it too!

Filter Reviews:
  • sky image
  • some
  • filter
  • areas
  • opportunity
Paul H.
United States United States

Expensive but amazing!

This an amazing filter. It allows some of us live in the light polluted areas and do not always have opportunity to see the very dark sky to produce better deep sky image. So far, only had one clear night and tried once. Very happy.

OPT Telescopes Radian Telescopes 2 Triad Ultra Filter Bundle Review
Connor K.
United States United States

Exceptional filter, exceptional results, but for a hefty price (and not friendly with all CMOS sensors!)

I bought this filter used from OPT at a discount, but I was still hesitant given the pretty exorbitant cost. The L-Enhance has done me wonders and with an ~$800 price jump between the two I took a bit of mulling it over before pulling the trigger. I was fortunate enough to be able to put it to several days use right away with great nights. With only my first 5 minute sub of the Heart nebula I knew the filter was truly exceptional. Like I said, the L-Enhance has been worth every penny. But when that first sub with the Triad rolled in, I was floored. ZERO signs of light pollution. Detail was already jumping out and had real, deep coloration. I proceeded to collect 9 hours of the heart and 13.5 hours of the Rosette. The only thing holding back the results of this filter are my own novice processing skills. The data acquisition was truly stellar on all accounts. Processing noise was almost comically simple with how incredible pristine the data and detail was. While OSC can't truly shoot true SHO, the different wavelengths it passes make false color processing so much more gratifying than with a duo-band. However, if you use an ASI294MC Pro, DEFINITELY KEEP READING... It does what it's meant to do and exceeded all expectations in that regard. However, I knock off 1 star for what I consider to be 2 VERY important points. 1) The price point. Yes, it is a quad band. Yes, the band passes are quite incredible. But unless you have the eye and skills to make the most of the filter, I wouldn't ever suggest it is worth such an increased cost over the L-enhance or L-extreme. If you're really solid in your skills or are looking to make that next big step, then great, this is a great buy, but otherwise the leap in obvious details or colors is hardly worth the price gap. If you do this for yourself or non-astrophotography friends and family where you aren't looking to wow professionals, this filter is probably worth leaving on the wish list for now. 2) ***The Triad Ultra IS NOT ABLE TO TAKE PROPER FLATS WITH THE ASI294MC Pro SENSOR.*** I learned this the hard way, and this is single handedly my biggest regret in this filter and even pushed me to consider a return before discovering a work around. If you are using this with an ASI294MC Pro sensor, you will notice that your flat frames will have this horrendous splotchy, almost X shaped pattern, across the field of view. You can kiss smooth, normal flats gradients good bye. At first I thought I had botched the flats settings, until it became more and more obvious that my camera only produced the pattern with this filter only. A quick look online found very few, but very vocal, ASI294MC owners who were experiencing this same issue. One thread on cloudy nights explain they contacted ZWO who thought perhaps it was a faulty sensor. They were, in fact, able to recreate the problem consistently and as far as I've been able to deduce it's a situation of "not our problem." I found this very disappointing, as the ASI294MC Pro is pushed as one of the best sellers online and extremely popular. I never would have even thought of such a problem existing, but here we are, and it is with arguable one of the most popular OSC cmos cameras available. So if you have an ASO294MC Pro, STEER CLEAR. The workaround discussed online was using the L-enhance for flats as the main error is in the deep reds of Sii having issues with the bayer matrix, and as far as I can tell, it's been perfect. But that's just silly if you don't already own the L-enhance to spend that on top of the Triad just to take decent flats. It's a really crying shame that the issue isn't so well known as of yet given the popularity of the camera, because I know the number of folks finding this out the **** way is only going to keep going up. I hope OPT can look into the matter and properly state the warning of this online. Had I known, I wouldn't have made the purchase and invested elsewhere. (This is NOT OPT's fault, I just hope they can warn future buyers.) EXCELLENT FILTER. EXCELLENT RESULTS. DEBATABLE COST/REWARD. AND NOT IDEAL FOR ASI294MC CAMERAS.

OPT Telescopes Radian Telescopes 2 Triad Ultra Filter Bundle ReviewOPT Telescopes Radian Telescopes 2 Triad Ultra Filter Bundle Review
Anthony F.
United States United States


This was one of the best purchases I've ever made!! OPT was right on the money! Fantastic performance. I used an Explore Scientific ED165-FPL53 Air-Spaced Triplet Refractor, ASI2600 CMOS one-shot dedicated astronomy color camera at a temperature of -24.5 Celsius and the Triad Ultra Quad-Band Narrowband filter to shoot NGC 2237.

OPT Telescopes Radian Telescopes 2 Triad Ultra Filter Bundle ReviewOPT Telescopes Radian Telescopes 2 Triad Ultra Filter Bundle Review
Michael S.
United States United States


I am sooooooo excited about this filter! 100% get this if you use OSC. I cannot believe the difference using this. I am not paid in any way. This filter is really good. Color is preserved and the nebula contrast is perfect. Was a skeptic, but this filter will greatly decrease your integration time and increases snr. No scam. Some halo’s on brighter stars, though

OPT Telescopes Radian Telescopes 2 Triad Ultra Filter Bundle ReviewOPT Telescopes Radian Telescopes 2 Triad Ultra Filter Bundle Review
Vladimir D.
Russia Russia

The filter wheel is in one position - Triad Ultra

I try to shoot from my backyard in zone 8 on the Bortle scale. A set of different filters is available to combat light pollution. I used to buy filters for a telescope. But after a little experience with the Triad Ultra, I came to the conclusion that I should buy a good telescope for this filter :). I'm new to this business, with only a few months of experience in astrophotography, but my first shots with this filter impressed me. This is by far the bestseller among filters, although not the cheapest :).

OPT Telescopes Radian Telescopes 2 Triad Ultra Filter Bundle ReviewOPT Telescopes Radian Telescopes 2 Triad Ultra Filter Bundle ReviewOPT Telescopes Radian Telescopes 2 Triad Ultra Filter Bundle ReviewOPT Telescopes Radian Telescopes 2 Triad Ultra Filter Bundle ReviewOPT Telescopes Radian Telescopes 2 Triad Ultra Filter Bundle Review
Arturo B.
United States United States

Great Filter

I bought my filter a few months ago and I am delighted here, I have other similar and very good filters but this one I highly recommend, it is not cheap but it is worth it

OPT Telescopes Radian Telescopes 2 Triad Ultra Filter Bundle Review