Dismiss Notice
New Cookie Policy
On May 24, 2018, we published revised versions of our Terms and Rules and Cookie Policy. Your use of AstronomyConnect.com’s services is subject to these revised terms.

More Views

William Optics 1.25" Carbon Fiber Dielectric Star Mirror Diagonal

4.6 (17 Reviews) Read Reviews Write Review
Brand William Optics
Part Number D-125D
Availability

Product Info

Manufacturer Description

You do not have to renounce having a quality 1.25" diagonal! Built like the renowned 2" WO diagonal, this dielectric coating diagonal will give you all you need for a lifetime of observations with the highest achievable brightness, contrast and sharpness. A premium product at a discounted price. Check it out and see the difference between a "budget diagonal" and a real bargain!

Features:
- Top-notch Performance and Brightness
- Dielectric coating allows 99% reflectivity.
- 10mm thick substrate flat for optimal image stability.
- Polished to 1/10th wave accuracy.
- Accurate design guarantees constant alignment. No further alignment needed.
- Strikingly Beautiful - Patented, elegant design.
- High-quality machining out of the best aluminum. real Carbon Fiber side plates.
- Internally antireflection threaded for highest contrast.

Meticulous Craftsmanship Lock screw for eyepiece/adapter. Big, knurled thumbscrews easy to turn even with gloves on.

Superbly Constructed - Compression ring to prevent barrels marring. - Internal safety stop prevents 1.25 barrels from hitting the mirror.

Why W.O. diagonals do not feature an Adjustable alignment system? - Having an adjustable alignment system is an admission that the diagonal can go out of collimation due to poor mechanical construction. Thanks to the patented design of WO diagonals, you will always have a diagonal that performs perfectly like the first day you got one!

Specifications:
Outside diameter: 32mm, threaded to fit a variety of filters.
Weight: 9.5 oz

Reviews

4.6 (Based on 17 Reviews) 88% of reviewers recommended this product.
Rating Distribution
Sort by
  • Date
  • Rating
  • Useful
    1. Guest

      Skill Level
      Unknown
      Time with Product
      Unknown
      User Notes:
      Review by rcastronomy of Rapid City, SD.
      1386892800
      Dec 12, 2013

      2.0 OK Diagonal but eyepiece catch sometimes

      Pros:

      Lightweight

      Cons:

      Difficult to Use

      Comments:

      I like the diagonal but I find that eyepieces don't go in and out of the diagonal smoothly. The compression ring seems to catch sometimes. Not a huge deal but it shouldn't do that.

      Bottom Line: Would you recommend this item? No
      Was this review helpful? Yes / No

      This review was provided courtesy of AgenaAstro.com

    2. Guest

      Skill Level
      Unknown
      Time with Product
      Unknown
      User Notes:
      Review by Furlan of Brazil - Sao Paulo.
      1386633600
      Dec 9, 2013

      5.0 Would buy again

      Pros:

      Easy to Use,Strong Construction,Quality Lenses

      Cons:

      Comments:

      The product purchased was really what I wanted.

      Bottom Line: Would you recommend this item? Yes
      Was this review helpful? Yes / No

      This review was provided courtesy of AgenaAstro.com

    3. Guest

      Skill Level
      Unknown
      Time with Product
      Unknown
      User Notes:
      Review by PARISS of Asheville, NC.
      1374969600
      Jul 27, 2013

      5.0 Excellent Star Diagonal

      Pros:

      Accurate,Strong Construction,Easy to Use,Compact

      Cons:

      Comments:

      Good quality at the right price

      Bottom Line: Would you recommend this item? Yes
      Was this review helpful? Yes / No

      This review was provided courtesy of AgenaAstro.com

    4. Guest

      Skill Level
      Unknown
      Time with Product
      Unknown
      User Notes:
      Review by jms of France.
      1370304000
      Jun 3, 2013

      5.0 Good value for money

      Pros:

      Accurate,Strong Construction

      Cons:

      Comments:

      Since I bought Meade HD-60 series eyepieces for my Celestron Mak 127, the stock diagonal was not large enough to properly fit the new eyepieces. The body of the ep's was touching the diagonal's retaining screw.
      No more problem with the 1.25" William Optics diagonal wich is larger.
      Icing on the cake, the image is sharp, the diagonal is well built and looks sturdy.

      Bottom Line: Would you recommend this item? Yes
      Was this review helpful? Yes / No

      This review was provided courtesy of AgenaAstro.com

    5. Guest

      Skill Level
      Unknown
      Time with Product
      Unknown
      User Notes:
      Review by Fede of Argentina.
      1369958400
      May 30, 2013

      5.0 I would buy this product again

      Pros:

      Quality Lenses

      Cons:

      Comments:

      I used it in amateur astronomy applications. This diagonal have an unbeatable and superlative performance, more than dielectrics competitors .
      I used in a Maksutov Cassegrain 180 mm in where it is possible to catch more details of deep sky objects!!.

      Bottom Line: Would you recommend this item? Yes
      Was this review helpful? Yes / No

      This review was provided courtesy of AgenaAstro.com

    6. Guest

      Skill Level
      Unknown
      Time with Product
      Unknown
      User Notes:
      Review by Whiskers, cause I'm curious like a cat of Ely, MN.
      1360800000
      Feb 13, 2013

      5.0 Beautiful thing

      Pros:

      Easy to Use,Strong Construction,Lightweight

      Cons:

      Comments:

      This is simply a beautiful piece of hardware and it looks as good as it performs.

      Bottom Line: Would you recommend this item? No
      Was this review helpful? Yes / No

      This review was provided courtesy of AgenaAstro.com

    7. Guest

      Skill Level
      Unknown
      Time with Product
      Unknown
      User Notes:
      Review by Jeff of Harwood, MD.
      1360454400
      Feb 9, 2013

      5.0 Great Item

      Pros:

      Quality Lenses,Strong Construction

      Cons:

      Comments:

      Casual Astonomy. Very pleased with this diagonal.

      Bottom Line: Would you recommend this item? Yes
      Was this review helpful? Yes / No

      This review was provided courtesy of AgenaAstro.com

    8. Guest

      Skill Level
      Unknown
      Time with Product
      Unknown
      User Notes:
      Review by Steve of Southeast Louisiana.
      1348358400
      Sep 22, 2012

      5.0 Carbon Fiber Diagonal Worth Every Penny!

      Pros:

      Compression Ring,Strong Construction,Quality build

      Cons:

      Compression Ring Snags

      Comments:

      This is the second dielectric diagonal that I have owned, with an Astro-Tech being my first, and I can say that this Williams Optics diagonal is just as good, if not better, than the Astro-Tech. Optical quality is excellent, with bright and crisp images. Construction is solid and has a very robust feel when handling it. The compression ring holds all EPs firmly in place, with no lateral movement while seated in the diagonal. The only thing I can find real fault with is that some of my EPs, those with recessed channels on the chrome barrel, catch the edge of the compression ring when I try to remove them.

      Overall, I'm very satisfied with my purchase. HIGHLY RECOMMENDED!!

      Bottom Line: Would you recommend this item? Yes
      Was this review helpful? Yes / No

      This review was provided courtesy of AgenaAstro.com

    9. Guest

      Skill Level
      Unknown
      Time with Product
      Unknown
      User Notes:
      Review by Nakegun of Lake Elsinore, California.
      1341100800
      Jun 30, 2012

      5.0 Little brother

      Pros:

      Accurate,Strong Construction,Compact,Lightweight,Easy to Use

      Cons:

      Comments:

      I possessed the 2" version prior to this purchase, and was not surprised when this unit proved as capable as its larger sibling.

      Bottom Line: Would you recommend this item? Yes
      Was this review helpful? Yes / No

      This review was provided courtesy of AgenaAstro.com

    10. Guest

      Skill Level
      Unknown
      Time with Product
      Unknown
      User Notes:
      Review by Old Starman of Houston, Texas.
      1335744000
      Apr 29, 2012

      4.0 Excellent travel diagonal

      Pros:

      Quality Lenses,Accurate,Strong Construction

      Cons:

      Comments:

      Well made, nice diagonal. Relatively inexpensive. Important if it will be used on a travel scope (in case it was lost or broken)...I would not feel so bad

      Bottom Line: Would you recommend this item? Yes
      Was this review helpful? Yes / No

      This review was provided courtesy of AgenaAstro.com

    11. Guest

      Skill Level
      Unknown
      Time with Product
      Unknown
      User Notes:
      Review by Gordon of Washington, MI.
      1322006400
      Nov 22, 2011

      5.0 Superb quality at a great price!

      Pros:

      Accurate,Quality Lenses,Lightweight,Strong Construction

      Cons:

      Comments:

      I switched from the factory diagonal to this one and the difference was like night and day. Much crisper image quality. Definitely a good value for money. I highly recommend it.

      Bottom Line: Would you recommend this item? Yes
      Was this review helpful? Yes / No

      This review was provided courtesy of AgenaAstro.com

    12. Guest

      Skill Level
      Unknown
      Time with Product
      Unknown
      User Notes:
      Review by Padagan of Colorado, CO.
      1319932800
      Oct 29, 2011

      4.0 Solid quality and excellent clarity

      Pros:

      Accurate,Quality Lenses,Strong Construction,Easy to Use

      Cons:

      Comments:

      Impressed with the optic quality and the build. Worth the price and AgenaAstro service was great as well.

      Bottom Line: Would you recommend this item? Yes
      Was this review helpful? Yes / No

      This review was provided courtesy of AgenaAstro.com

    13. Guest

      Skill Level
      Unknown
      Time with Product
      Unknown
      User Notes:
      Review by Almir of Brazil.
      1319846400
      Oct 28, 2011

      4.0 Nice upgrade from the Celestron Diagonal

      Pros:

      Cons:

      Comments:

      Good upgrade to my Celestron SCT 8". Fine craftsmanship, sometimes catches the eyepiece inserted in the compression rings, keeps well collimated, good for astrophotos, although I prefer not using it for imaging.

      Bottom Line: Would you recommend this item? Yes
      Was this review helpful? Yes / No

      This review was provided courtesy of AgenaAstro.com

    14. Guest

      Skill Level
      Unknown
      Time with Product
      Unknown
      User Notes:
      Review by Suave of Arizona.
      1307145600
      Jun 3, 2011

      5.0 William Optics

      Pros:

      Strong Construction,Compact,Quality Lenses

      Cons:

      None

      Comments:

      This is not the first William Optics item that I have owned, and the third diagonal from their line, I buy and sell used telescopes as I bargain my way to what I really want. They make a quality product at a good price, this diagonal made a huge difference compared to the Meade diagonal that this 10" SCT came with.

      Bottom Line: Would you recommend this item? Yes
      Was this review helpful? Yes / No

      This review was provided courtesy of AgenaAstro.com

    15. MAK7

      MAK7 New Member

      Skill Level
      Unknown
      Time with Product
      Unknown
      User Notes:
      Review by Brad of Phoenix, AZ.
      1294012800
      Jan 2, 2011

      5.0 As usual, great W/O fit and finish

      Pros:

      Strong Construction,Compact,Solid build

      Cons:

      Comments:

      I have two W/O 2" diagonals, so when it came time that I actually needed a 1.25" diagonal, this was my first choice. Solid and well built, yet light weight. Every bit as good as I expected, just like the 2' models.

      Bottom Line: Would you recommend this item? Yes
      Was this review helpful? Yes / No

      This review was provided courtesy of AgenaAstro.com

    16. Guest

      Skill Level
      Unknown
      Time with Product
      Unknown
      User Notes:
      Review by unitron of Eaton, CO.
      1293408000
      Dec 26, 2010

      5.0 Great product

      Pros:

      Accurate,Compact,Strong Construction

      Cons:

      NO CONS

      Comments:

      Used for astro photography and the image was just as good or even better than my Orion dielectric.

      Bottom Line: Would you recommend this item? Yes
      Was this review helpful? Yes / No

      This review was provided courtesy of AgenaAstro.com

    17. Guest

      Skill Level
      Unknown
      Time with Product
      Unknown
      User Notes:
      Review by Ian of Rio de Janeiro, Brazil.
      1292803200
      Dec 19, 2010

      5.0 It's very transparent!

      Pros:

      Strong Construction,Lower Cost,Quality Lenses

      Cons:

      Comments:

      This diagonal is too much better then electric (Meade, Celestron). I do not saw the sky in a Meade or Celestron dieletric, but I believe in the Willian Optics Dieletric is the best cost benefit.

      Bottom Line: Would you recommend this item? Yes
      Was this review helpful? Yes / No

      This review was provided courtesy of AgenaAstro.com

    Sort by
    • Date
    • Rating
    • Useful