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 2" Carbon Fiber Dielectric Star Mirror Diagonal with SCT Adapter

4.7 (13 Reviews) Read Reviews Write Review
Brand William Optics
Part Number -
Availability

Product Info

Manufacturer Description

If what you are looking for is the highest achievable brightness, contrast and sharpness during critical observations with high-end instruments, WO 90-degree 2" mirror Dielectric star Diagonal is your choice. This dielectric diagonal features 100% real carbon fiber side plates that add that touch of class your scope deserves. A premium product at a discounted price. Check it out and see the difference between a "budget diagonal" and a real bargain!

This package consists of a refractor type diagonal (William Optics part # D-DIG2D-C) plus an SCT adapter (part # D-SCT-TA). You can easily use this on any refractor telescope with a standard 2" barrel, or on any SCT telescope with a standard SCT thread. To switch from a refractor diagonal to an SCT diagonal, simply unscrew the 2" nosepiece and screw on the included SCT adapter ring.

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.

Meticulous Craftsmanship
• 2"-to-1.25" eyepiece adapter included.
• Lock screw for eyepiece/adapter.
• Big, knurled thumbscrews easy to turn even with gloves on.

Strikingly Beautiful
• Patented, elegant design.
• High-quality machining out of the best aluminum.
• Internally anti-reflection threaded for highest contrast.

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

SCT Adapter Included With Each Diagonal
Also included with this diagonal is an SCT ring (William Optics part # D-SCT-TA) that makes your diagonal work on SCT telescopes or William Optics' ZS66 series as well! Get one diagonal, use it on ANY telescope! This SCT adapter sells for $35 by itself but is included in this diagonal package! Note that this adapter will work with the most recent ZS66 Series telescopes sold in the blue, white, or orange OTA versions. It will not work with the older black tube ZS66 Petzval Series.

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!

Features
• Ultra High Dielectric 99% reflectivity.
• Precision 1/10 lambda surface with 10mm-thick mirror.
• Adapter: 2"-to-1.25" with brass clamping ring.
• Inside diameter: 48mm, threaded to fit a variety of filters.
• Weight: 13.3oz/380g (w/o 1.25" adapter); 16.2oz/460g (w/ 1.25" adapter)

Reviews

4.7 (Based on 13 Reviews) 92% 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 PARISS of Asheville, NC.
      1374969600
      Jul 27, 2013

      5.0 Excellent 2" star diagonal

      Pros:

      Accurate,Easy to Use,Strong Construction

      Cons:

      Comments:

      I used the 2" star diagonal as a turning mirror on a custom refractor. It operated flawlessly, as I expected, from a William Optics product.

      Bottom Line: Would you recommend this item? Yes
      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 Dan of Gaithersburg, MD.
      1369958400
      May 30, 2013

      4.0 Nice diagonal

      Pros:

      Easy to Use

      Cons:

      Comments:

      I use this primarily with a Sky Watcher 100ED refractor and it makes a very nice pairing. I don't do a lot of visual astronomy (although I do use this diagonal to mount an imaging source camera), but when I do this diagonal is a definite upgrade over the Celestron star diagonal I used to have.

      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 Todd of Ft. Lauderdale, FL.
      1363996800
      Mar 22, 2013

      4.0 William Optics 2" Diagonal

      Pros:

      Lightweight,Easy to Use,Strong Construction

      Cons:

      Comments:

      Great quality diagonal. Only gave it 4 stars instead of 5 because there is quartz model that suppose to be higher quality. Never tried one of the quartz models. The CF is nice to look at and helps in the weight. I am extremely satisfied with my purchase. I would definitely recommend this diagonal. Agena was great about shipping right away. Great site and customer service!!

      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 Michael of Memphis, TN.
      1360454400
      Feb 9, 2013

      5.0 Great Star Diagonal

      Pros:

      Lightweight,Strong Construction,Easy to Use

      Cons:

      Comments:

      I bought this diagonal to use in my Explore Scientific AR152 refractor after dropping and damaging the stock diagonal. It's a very nice looking and solidly built star diagonal that feels like it should last for many years. I didn't notice a performance improvement over the stock diagonal, but it does improve the overall look of the telescope. The carbon fiber with the WO logo is very impressive looking.

      Others have reported problems with eyepieces catching on the brass compression ring, but I havent had that problem with any of my eyepieces. The diagonal holds all of my heavy 2" eyepieces very securely.

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

      This review was provided courtesy of AgenaAstro.com

    5. crsrs

      crsrs New Member

      Skill Level
      Unknown
      Time with Product
      Unknown
      User Notes:
      Review by crsrs31 of San Tan Valley, AZ.
      1348272000
      Sep 21, 2012

      5.0 I love this diagonal!!!

      Pros:

      Strong Construction,Easy to Use,Lightweight

      Cons:

      Comments:

      I have had other 2" diagonals, and this one is by far the best one yet! It's strong, and holds the weight of my heavy eyepieces without sagging. The coatings are exceptional in that the images viewed are much brighter than the others I've had. I also like the fact that the "Dielectric" coatings are much more durable, and can handle being carefully cleaned when need be.

      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 SteveG of Seattle, WA.
      1342396800
      Jul 15, 2012

      5.0 Very High-Quality Diagonal

      Pros:

      Great Baffling,Well built,High Reflectivity

      Cons:

      Comments:

      I purchased this William Optics diagonal after buying my 2nd WO refractor, so that the 2 would not have to share. This one, with its carbon fiber sides was matched with my Megrez 120, and it replaced another brand quartz diagonal. The two diagonals compare equally in reflectivity, but the WO diagonal has far better light baffling. I've had it for several months and can highly recommend this diagonal.

      Bottom Line: Would you recommend this item? Yes
      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 MacDougal of Cincinnati, OH.
      1335744000
      Apr 29, 2012

      5.0 WO 2" Carbon Fiber Dielectric Diagonal

      Pros:

      Strong Construction,Accurate,Easy to Use,Lightweight

      Cons:

      Comments:

      The diagonal is a great bang for the buck. Looks very nice and matches my carbon fiber OTA. The construction is excellent. Great price for a quality product. I would also like to add "Agena" is one of the best (maybe the best) online store I have dealt with. Excellent, Outstanding service and very prompt to answer any questions you might have.

      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 Phil of Seattle.
      1324857600
      Dec 25, 2011

      5.0 Excellent Diagonal

      Pros:

      Lightweight,Easy to Use,Strong Construction,Quality Lenses

      Cons:

      Comments:

      Having both the refractor and SCT nosepieces allows use in both my refractors, SCT and MCT--works very well in all and provides great flexibility. Only caveat with the interchangeable nosepieces is to make sure they are screwed in tightly otherwise a heavy EP can cause the diagonal to rotate. Very nice diagonal functionally and the aesthetics are first class.

      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 Shadow2097 of Pittsburgh, PA.
      1292803200
      Dec 19, 2010

      5.0 Top notch diagonal

      Pros:

      Strong Construction,Accurate

      Cons:

      Heavy

      Comments:

      Very sturdy and well built diagonal. It can handle the largest and heaviest eyepiece without any kind of bending, flexing, or distortions.

      It's fairly heavy, so if you're used to balancing a scope with a 1.25" diagonal, be prepared to find a new balance point. Otherwise, it's definitely worth the upgrade.

      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 skygeek of Los Angeles.
      1292716800
      Dec 18, 2010

      5.0 Crystal clear images

      Pros:

      Strong Construction

      Cons:

      Heavy

      Comments:

      This is an excellent diagonal. It's so good that this is my second one that I had bought. I do a lot of astro imaging and the images are bright and clear. I highly recommend this product.

      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 JohnR of Athens, GA.
      1243382400
      May 26, 2009

      5.0 High Quality,good price

      Pros:

      Compact,Quality Lenses,Accurate,Strong Construction

      Cons:

      Comments:

      Goes perfect with my 127 ED APO TRIPLET. I guess in the near future I may try WO's newest diagonal.

      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 Cosmo of OR.
      1239062400
      Apr 6, 2009

      5.0 Excellent Diagonal

      Pros:

      Cons:

      Comments:

      Excellent clarity and brightness -- beautiful styling and finish

      The tight compression ring problem seems to be common -- I experienced the same with a Meade 2" and other adaptors. It helps some to spread and reposition the ring with your fingers first.

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

      This review was provided courtesy of AgenaAstro.com

    13. jonm

      jonm New Member

      Skill Level
      Unknown
      Time with Product
      Unknown
      User Notes:
      Review by Jon of Fort Myers, FL.
      1223078400
      Oct 3, 2008

      3.0 Beautiful piece of gear...but

      Pros:

      Strong Construction

      Cons:

      Difficult to Use

      Comments:

      Very nice quality and bright views but, on the one I received, I would have to jiggle an eyepiece to get it to drop past the brass compression ring and seat in the diagonal. The bottom edges of all my different eyepieces would hang up slightly on the compression ring no matter how loose the set screw was. It seems the ring was just not recessed enough. I may try another unit before switching brands.

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

      This review was provided courtesy of AgenaAstro.com

    Sort by
    • Date
    • Rating
    • Useful