Celestron SCT 2″ XLT Mirror Diagonal Review

The Celestron SCT 2″ XLT Mirror Diagonal is an excellent star diagonal made specifically to thread to the rear cell of Celestron 5″, 6″, 8″ and 9.25″ Schmidt Cassegrain Telescopes. It is a solid diagonal, and has an excellent anodized, matte black finish. The excellent construction is what stood out to me most when I first purchased the diagonal.

This diagonal utilizes Celestron’s Starbright XLT coatings to give a mirror that reflects about 96% of incoming light. These excellent coatings allow more light to reach your eye, which helps increase the surface brightness of faint deep sky objects. Since using this diagonal, I have been able to better resolve the stars in Globular Star Clusters, and have had an easier time resolving faint Planetary Nebula, such as the Ring Nebula.

In addition to the build quality and excellent coatings, the diagonal allows 2″ eyepieces to be used. 2″ eyepieces will allow the user to delve into more of their Schmidt Cassegrain’s light cone than 1.25″ eyepieces will. This also increases the amount of light that reaches your eye, making it easier to resolve dim objects.

Having the ability to use 1.25″ eyepieces and 2″ eyepieces really makes the Schmidt Cassegrain Telescope a versatile instrument. Couple that with the build quality and coatings on this diagonal, and you have an excellent product from Celestron.


DENSUTUBE2008 says:

Excellent information Thanks!

MrWakeupUSA says:

If I get this, do I need 2″ eyepieces? How much loss do you experience with 1.25″ eyepieces? I am a newbie,any and all help is appreciated…

nelson rivera says:

Again a great video Slymin with lots of awesome information , Im in the market for a great telescope , and my decision is made (the Celestron nexstar) however i also saw a video which recommends a Hyperion zoom , is this a good buy as well as the C sct 2″ xlt m d ? thank you , i was thinking on buying the lens kit ,but no anymore ,thank you

John Doe says:

I use this with the Celestron Luminos 31 mm Eyepiece, yes it weights a ton, but worth it.

EddWar says:

I have that diagonal and is really good.

nelson rivera says:

Based on your video reviews i made a list of things to buy , im so exited your are answering my questions

Bruce Darling says:

Interesting that your Celestron 2” diagonal differs from the #93519 that came with my new EdgeHD 9.25. Mine lacks compression rings for either the 2” tube or the 1.25” adapter – just plain metal screw tips into the sides of the eyepieces. It was completely unworkable with any 2” Luminos eyepiece and marred everything I put into it. Add the inability to hold the orientation of the attachment to the OTA back under any kind of weight and it was a total no-go. I ended up with a Baader Clicklock attachment to the OTA tied to a Baader Clicklock 2” diagonal. I repurposed the 1.25” adapter from my Celestron 2.5x 2” Barlow (which does have a compression ring) and am very happy with the result. Just very unhappy about buying a new $4000 scope kit and having to shell out a fistful of more $$$$s to make it workable. Wonder what your model # is? Not all Celestron 2” diagonals have compression rings!

Ray's Astrophotography says:

Slymin, I always watch your videos. They are all very comprehensive. Great job again.

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