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Celestron Dielectric Star Diagonal, 2" with Twist-Lock

SKU: CNDIM2XSD MFR: 93573
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Key Features

  • Enjoy over 99% reflectivity with this Celestron star diagonal for brighter telescope views.
  • Achieve diffraction-limited optical quality with this 2" telescope diagonal for crisp images.
  • Secure your eyepieces with the convenient Twist-Lock mechanism on this star diagonal.
  • Features a single compression ring to protect your valuable telescope eyepieces from damage.
  • Reduce glare and enhance contrast with the glare-threaded, flat black barrel interior.
  • Easily attach 1.25" filters to your telescope with the built-in threads on this diagonal.
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Q&A

Questions & Answers

Shopper : What is the optical length of this Celestron 2" Dielectric Star Diagonal?
Jayman C : Will the 2" thread directly on your the back of a celestron evolution 9.25?Kirk S : My diagonal threaded directly onto my 40+ yr old C8. I did, however, need to make a ring shim as it wouldn't tighten completely. Can be made from thin rubber or aluminum.BA L : Short answer is yes. The SCT thread (supplied) on the Celestron 2” Diagonal is the same. Screw off the old Diagonal...screw on the new.JEFF Q : It does on my 9.25 Edge.BA L : Yes. The SCT Thread (supplied) will be the same as the stock Diagonal it is replacing.MARTIN N : The likely answer is yes; it threads directly on the 8” Edge HD. If you download the support docs at Celestron for this diagonal, it claims to fit the standard 2” SCT thread which is supposed to be used on almost all the Celestron SCTs. I started with the threaded part but switched to the 2” tube option with a Baader 2” Clicklock attached to the SCT. This allowed me to insert a 2” light pollution filter on the tube end and insert it into the scope.
MARK S : does it include the 3 protective caps?MIKE K : Yes, all dust caps are included.

Reviews about this item

Review Summary

2023-09-07T13:58:56

Rated 5 out of 5

Unbelievable change

Fantastic improvement in my telescope. Crystal Clear Viewing. And a fantastic price, thank you.

DONNY E.

2023-05-23T00:00:40

Rated 5 out of 5

This small upgrade makes using my scope a little bit better

A really high quality star diagonal.image quality is clear n crisp which is always the case with celestron products. And the twist lock feature is a game changer. No more tiny little thumb screw gouging my eye pieces. The twist ring holds firmly n evenly. The orange ring not only looks sharp but stands out allowing u to change eye pieces in the dark more easily.

steve s.

2023-02-24T08:37:36

Rated 3 out of 5

OK not WOW

decided to replace the basic mirror 1.25 diagonal that came with the C8 Edge HD. A mystery why a scope with high end optics has a basic mirror diagonal - defeats the purpose of getting an HD visual. My issue with this 'twist lock' is that it really is more of a 'screw on' where you need to turns it a lot of revolutions to get the collar tight on the eyepieces. Moreover, you REALLY have to tighten the attaching collar to the back of the OTA otherwise it is regularly loosening, especially with with 2" eyepieces. My fear is overtightening/stripping the threads to stop the diagonal from flopping around. THAT IS A CHEAP DESIGN. Is the actual mirror visual a marked improvement from the original ? - hard to say. I bounced back and forth using the original 1.25 eyepiece - no discernible improvement in light/clarity. On the fence. Best comment is "OK, not WOW".

CHRISTOPHER B.

2022-03-16T12:04:41

Rated 5 out of 5

Quality product as advertised.

Perfect fit on my sct and the feel is solid. I was worried about the weight of a 2? diagonal upgrade but it?s a little lighter that some of the others. My Nexstar seems fine with it. My 1.25 eyepieces fit nicely in the adapter and my 2? eyepiece fits perfectly. Love the higher visibility orange lock collars. Overall pleased with the shipping and product.

DONALD N.

2021-11-19T01:20:12

Rated 5 out of 5

Celestron 2 inch telescope diagonal review.

I was very impressed with the fit and finish of this Celestron telescope diagonal. This allows 2 inch eyepieces to be used, which dramatically increases the quality of astronomical viewing. I have already recommended this necessary upgrade to fellow astronomy club members.

CAROL S.

2021-11-15T08:48:29

Rated 5 out of 5

Celestron Dielectric Star Diagonal

Love the twist-lock mechanism for holding my eyepieces and the eyepieces stay secure. No moving or sliding around using the little thumb screws, which always seem to strip out after awhile. The dielectric is a huge upgrade over a standard diagonal.

Patrick E.

2021-10-26T09:11:56

Rated 5 out of 5

A must upgrade for your telescope

Image is much brighter and clearer than standard stock diagonal

PHILIP I.

2021-09-26T09:05:08

Rated 5 out of 5

Excellent addition to my celestron

Excellent piece - very fine craftsmanship and makes swapping pieces very fast. And yes, you can use it with the focal reducer, as well. Don't need to listen to those that say there is no purpose for it - it actually helps get the cheap sv305 to take some ok shots.

COREY S.

2021-09-09T08:56:30

Rated 5 out of 5

Very well constructed

Great product

David C.

2021-09-01T08:38:39

Rated 5 out of 5

Celestron Dielectric Star Diagonal 2"

Mirror quality great, and overall materials used high quality.

Mark W.

2021-08-25T12:23:10

Rated 5 out of 5

great for sct

very well built love the twist lock still waiting for good skys to really take for test drive

DANIEL Z.

2021-05-26T12:24:23

Rated 5 out of 5

Nice Upgrade

I bought this to replace the diagonal that was missing from a used Celestron 9.25 CPC HD scope that I bought. Wow, I am spoiled now! It is more convenient to change eyepieces now than before. It is a nice upgrade, and I'm glad I bought it.

VERONICA L.

2021-05-20T03:33:21

Rated 5 out of 5

Great upgrade for evolution

Upgraded my Evo 9.25 with this, making it much quicker and easier to attach eyepieces. The thumbscrews on the stock diagonal interfered with a couple of my eyepieces but this one fixes that problem. Eyepieces now feel more securely attached as well. Best money spent so far.

Kenneth L.

2021-05-13T10:24:15

Rated 4 out of 5

The jury is still out.

Didn't get a chance to use it yet. Seems to be well made. Fits eyepieces well too.

HORACE C.

2021-03-01T08:42:29

Rated 5 out of 5

Perfect for my scope

This is an outstanding star diagonal. Great optics.

Raymond S.

2020-11-26T19:11:10

Rated 5 out of 5

KZ

Perfect device!

KRISTINA Z.

2020-11-16T10:32:50

Rated 5 out of 5

1.25" dielectric star diagonal

works great

DAN B.

2020-10-14T09:30:05

Rated 5 out of 5

Works Well!

Good quality for the price.

CURTIS R.

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Celestron Dielectric Star Diagonal Specifications

  • Reflectivity

    Over 99%

  • Optical quality

    Diffraction limited

  • Eyepiece holder

    1.25", Twist-Lock

  • Compression ring

    Yes, single ring

  • Housing construction

    Machined aluminum black anodized

  • Barrel interior

    Glare threaded and painted flat black

  • Threads for filters

    Yes, 1.25"

  • Dimensions

    114.3mm x 50.8mm x 88.9mm (4.5" x 2" x 3.5")

  • Weight

    7.5 oz (212.6 g)

  • UPC Code

    050234935739

About Celestron Dielectric Star Diagonal

FEATURED REVIEWS

Nice Upgrade

By VERONICA L.

I bought this to replace the diagonal that was missing from a used Celestron 9.25 CPC HD scope that I bought. Wow, I am spoiled now! It is more convenient to change eyepieces now than before. It is a nice upgrade, and I'm glad I bought it.

Great upgrade for evolution

By Kenneth L.

Upgraded my Evo 9.25 with this, making it much quicker and easier to attach eyepieces. The thumbscrews on the stock diagonal interfered with a couple of my eyepieces but this one fixes that problem. Eyepieces now feel more securely attached as well. Best money spent so far.

Find the ultimate upgrade for your telescope with the Celestron Dielectric Star Diagonal, 2" with Twist-Lock. This premium star diagonal is designed to enhance your stargazing experience by delivering brighter, sharper images without the need for a new telescope.

This high-quality star diagonal is engineered to reflect the telescope's light path at a 90-degree angle, offering a more comfortable viewing angle. The glass is fortified with 58 layers of dielectric coatings, ensuring an over 99% reflective surface. This superior reflectivity guarantees maximum light transmission to the eyepiece, enhancing the clarity and brightness of your celestial observations.

The Celestron Dielectric Star Diagonal is compatible with both 2" and standard 1.25" eyepieces, thanks to the included stepdown adapter. This flexibility allows you to enjoy a wider field of view with larger eyepieces or use your existing 1.25" eyepieces.

The innovative twist-lock eyepiece holder not only secures your eyepieces but also ensures optimal alignment between the telescope and eyepiece. Unlike traditional thumb screws, the twist-lock mechanism won't scratch or engrave the barrel of your eyepieces, preserving their quality and longevity.

The diagonal features an integrated 2" barrel stop, protecting the mirror from potential damage by long-barreled 2" accessories. Crafted from machined black anodized aluminum, all mechanical parts of the diagonal are robust and durable. The twist-lock rings are orange anodized for easy visibility.

The interior of the Schmidt-Cassegrain adapter and 2" barrel are threaded and painted flat black to prevent glare, ensuring an uninterrupted viewing experience. This diagonal also comes with two interchangeable barrels, offering versatility in connecting to a wide range of telescopes without additional adapters.

The Celestron Dielectric Star Diagonal, 2" with Twist-Lock, stands out in terms of reflectivity and optical quality, delivering top performance with an over 99% reflective mirror and diffraction-limited optical quality. By simply replacing your existing diagonal with this premium one, you can significantly enhance the views from your telescope.

Celestron Dielectric Star Diagonal Features

  • Enjoy better views through your telescope with this premium diagonal featuring diffraction-limited optics and dielectric coatings
  • Provides a 90 degree viewing angle, perfect for more comfortable viewing through refractor and Cassegrain-type telescopes
  • 58 layers of dielectric coatings provide an over 99% reflective surface, ensuring the maximum amount of light collected by the telescope reaches the eyepiece
  • Twist-lock keeps the eyepiece centered in the diagonal to provide better optical alignment
  • Includes a stepdown adapter, so the diagonal accepts eyepieces, Barlow lenses, threaded filters, and other accessories in both 2" and 1.25" sizes
  • Two interchangeable adapters allow you to switch between a Schmidt-Cassegrain thread adapter and a 2½ barrel adapter so you can use this diagonal with a wide variety of telescopes

Warranty Information

This product has a limited warranty of 24 months for parts and 24 months for labor.

Key Features

  • Enjoy over 99% reflectivity with this Celestron star diagonal for brighter telescope views.
  • Achieve diffraction-limited optical quality with this 2" telescope diagonal for crisp images.
  • Secure your eyepieces with the convenient Twist-Lock mechanism on this star diagonal.
  • Features a single compression ring to protect your valuable telescope eyepieces from damage.
  • Reduce glare and enhance contrast with the glare-threaded, flat black barrel interior.
  • Easily attach 1.25" filters to your telescope with the built-in threads on this diagonal.

What's in the box:

  • Celestron Dielectric Star Diagonal
  • 2 " with Twist-Lock
  • 1.25 " Stepdown Adapter to accept 1.25 " Eyepieces
  • Schmidt-Cassegrain Thread Adapter
  • 2 " Barrel Adapter