William Optics 1.25'' DURA-BRIGHT Dielectric Diagonal

William Optics 1.25" DURA-BRIGHT Dielectric Diagonal

  (12 Reviews)
✓ 2 year warranty


10x in stock shipped 1-2 working days

About this product

Model:  WOdielectric125
Part Number:  D-125D-C-DB

Offers a noticeable improvement in brightness, contrast and overall sharpness when compared to budget diagonals!

  • Dura-Bright thick mirror and dielectric mirror coatings for 99% reflectivity.
  • Precision 1/12 lambda surface accuracy.
  • 12mm-thick mirror substrate.
  • Threaded to accept 1.25" filters.
  • Compression ring to prevent barrels’ marring.
  • Internal safety stop prevents 1.25” barrels from hitting the mirror.

Introducing New 2014 model William Optics Dura-Bright diagonal - a dramatic step forward in the evolution of mirror diagonals! This 90° 1.25"mirror-type star diagonal has a Dura-Bright thick mirror and dielectric mirror coatings for 99% reflectivity which provides higher contrast and resolution during critical planetary, lunar and binary star observations.

Dura-Bright features 100% real carbon fiber side plates that add that touch of class your scope deserves.

The WO 1.25" Dura-Bright Diagonal was designed with several unique features to provide optimum performance and years of use.

Top-Notch Performance and brightness
• Dielectric coating allows 99% reflectivity.
• high precision 12mm thick mirror substrate flat for optimal image stability.
• Polished to 1/12th wave accuracy.
• Accurate design guarantees constant alignment. No further alignment needed.

Meticulous Craftsmanship
• Lock screw for eyepiece/adapter.
• Big, knurled thumbscrews are easy to turn even with gloves on.
• Threaded for 1.25" Filters.

Strikingly Beautiful
• Patented, elegant design.
• High-quality machining out of the best Aluminium.
• Internal antireflection baffling for highest contrast.
• Real Carbon Fibre side plates

Superbly Constructed
• Compression rings (both on diagonal and adapter) to prevent barrels from marring.
• Internal safety stop prevents 2" barrels from hitting the mirror.
• Designed for high-end scopes.


ReflectivityUltra High Dielectric 99% reflectivity.
MirrorPrecision 1/10 lambda surface with 12mm thickness mirror for best quality.
Accessories2"- 1.25" adapter with brass clamping ring,includes
MeasurementsInside diameter (48mm): threaded to fit a variety of filters.
WeightWeight : 210g

Customer reviews

Average Rating (12 Reviews):  
Write a Review and share your opinions!

Rating (max 5):  
William Optics 1.25" DURA-BRIGHT Dielectric Diagonal
Friday, 4 December 2020  | 

Quality diagonal that delivers improved performance. Definite increase in brightness in the viewed image, and a good choice as an upgrade to the supplied star diagonal.

Rating (max 5):  
Tuesday, 8 September 2020  | 

Not been used much due to cloudy skies locally. Excellent quality build as you would expect from this provider. Wonderful customer service as always from FLO, thanks all!

Rating (max 5):  
Very high quality
Wednesday, 12 August 2020  | 

Exactly what you would expect from William Optics. Well designed and beautifully made.

Rating (max 5):  
First Class Service
Tuesday, 5 May 2020  | 

First purchase from FLO, faultless transaction, fast and efficient. Just purchased more items. Highly recommended. Thank you.

Rating (max 5):  
William Optics 1.25" DURA-BRIGHT Dielectric Diagonal
Friday, 7 February 2020  | 

I spent sometime reviewing a number of Diagonals to replace my standard issue 1.25 Celestron one, which came with my Nextstar SLT 6" SCT. Really in the end, I kind of narrowed it down to a Celestron "Twist-Lock", Tele-Vue or WO DURA-BRIGHT.

Well, I could have spent over 50 or more on the Tele-Vue, but when I ordered and received the WO DURA-BRIGHT (very nicely packed by FLO) I was very impressed!! Firstly, if you compare your Diagonal which was supplied with your Scope, (just look through it with your eyeball) with the DURA-BRIGHT, the difference is blatantly OBVIOUS. The Image is Bright and has More Contrast. The Build Quality is very good, and I had NO problems extracting my Celestron X-Cel LX eyepieces (some people mentioned issues with the compression ring, binding on the eyepiece undercut, with this type of locking system, which is used by several manufacturers by the way) all I can say is, I haven't found any Problem as such, just don't over tighten the locking Screw, and a very slight lift and wiggle, as you extract the eyepiece, if you ever find it necessary I suppose.).

Rating (max 5):  
So good I purchased this twice!
Wednesday, 4 September 2019  | 

When I purchased my Tak 76 in 2016, I needed a high quality diagonal to go with it; I travel a lot so only use 1.25 eyepieces, Ian King had sold out of the Tak prisms, and suggested that this was a great quality diagonal. It's been superb, traveled lots with it, used extensively at Seething, the Astro Camp and the Astro Fam in Confolens for a Messier Marathon...Sadly, I managed to break my original in the early hours of one morning. FLO was the first website I went to, to replace it. High quality, lightweight and well made; holds my 24mm Panoptic and 9mm Nagler with ease, has a compression ring (i think that's the term) so you don't make marks onto the barrel of the eyepieces. The barrel that you insert into the telescope will unscrew, which is perfect for helping you blow away any dust that will accumulate after many uses...Has a 2 year guarantee, and unless you're a "butterfingers" should last a long time!

Rating (max 5):  
Could Not Resist !
Friday, 19 October 2018  | 

As soon as I took my Celestron Edge telescope out of it's box I knew I wanted to upgrade certain items. I'm just like that... This diagonal looked the part on the website and face to face it does not disappoint. Excellent build quality and superb looking clear mirror. The fixing look more substantial too. I am fully trusting this to hold my Vixen eyepieces and to look good while doing it. Recommended !!

Rating (max 5):  
Great Product
Wednesday, 13 June 2018  | 

Great Product

Rating (max 5):  
Great product.
Tuesday, 6 February 2018  | 

Great product, great service! But I wish they'd stop asking for feedback every time I buy something!!

Rating (max 5):  
Solid design
Monday, 1 September 2014  | 

This diagonal looks good and feels even better. Compared with a stock Skywatcher diagnoal, the build quality is far superior. I used this diagonal with a Celestron X-Cel LX (25 mm) and the view was crisp and flat to the very edge of the FOV.

Read all 12 customer reviews...


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