William Optics 1.25'' DURA-BRIGHT Dielectric Diagonal

William Optics 1.25" DURA-BRIGHT Dielectric Diagonal

  (6 Reviews)
✓ 2 year warranty


Usually shipped 15-20 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 aluminum.
• Internal antireflection baffling for highest contrast.
• Real Carbon Fiber 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 (6 Reviews):  
Write a Review and share your opinions!

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.

Rating (max 5):  
Don't be deceived!
Thursday, 11 October 2012  | 

People look at this diagonal and assume that - due to its hefty build - it must be of high quality.

Unfortunately it has two problems which are serious enough to strike it off your wish list:

1) Firstly, the internal safety-stop actually obstructs light - vignetting the edge-of-field on super-wide eyepieces.

2) The safety-stop - and some other parts - have shiny surfaces which casts glancing light reflections into the eyepiece, causing annoying glare on the moon and bright stars.

Best choose something else.

FLO Response: There has been no attempt at deception Jeremy, please contact us with your purchase details so we can arrange a full refund

Rating (max 5):  
Very high quality diagonal
Tuesday, 31 May 2011  | 

I've often heard it said that a diagonal upgrade gives you nebligible optical improvement, but that doesn't mean it isn't worthwhile.

You may not notice a significant difference observing with it, but what matters is build quality. A well-made diagonal holds eyepieces more securely and accurately in the optical train.This diagonal is extremely well made, and a real joy to use. It's got everything right: tapered barrel for a secure fitting, very stable body with carbon fibre panels, excellent compression ring holder with lovely large thumbscrew, lightweight, optically superb, and, very importantly, a perfectly well-justified pricetag, which means it's well-worth it even if you can't see any difference!

I would see no reason to spend more on a 1.25" diagonal.


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