Celestron 93573 Dielectric Star Diagonal 2" with Twist Lock

Excellent item ,fast shipping.

Love the jump from the stock 1.25" diagonal to this monster! Even better when adding 2" eyepieces, but so cool that I can use my 1.25" EPs as well. Love the twist lock feature. Makes it very simple to swap EPs, and they are held confidently in place. Totally worth it!

I do not have an expensive telescope (a 5" Maksutov) but the telescope glass is pretty good. The problem is the 5" aperture which only allows so much light to come in. This means the optics attached to the telescope need to be as high quality as you can afford so you can get all the light possible to the eyepiece. For this I purchased Celestron's dielectric star diagonal because it is much better than the original cheap diaganol. It is easy to work with, too, because of the special twist lock it has which lets me change eyepieces easily and safely. I'm surprised more amateur astronomers don't start with buying a better diagonal like this one. When I upgrade my telescope the Celestron Star Diaganol can work with the new scope too.

Nice diagonal for $200, especially if you own a SCT. The only issue like others have mention, is it does not have enough thread depth for the 6.3 focal reducer corrector. Others have swapped the SCT ring from the 1.25 stock visual back. This does work fine and I got 1.5 turns onto the focal reducer. The solution I prefer is to purchase the Astromania adapter. This will convert SCT threads to M42 or M48 with M48 adapter. The diagonal uses M48. The adapter does not reduce the light path diameter to the diagonal. I use the astro adapter to attach all kinds of stuff to my C8. The really nice thing is it provides two full turns to the focal reducer. This allows significant more weight bearing. One star off for not thinking about the 6.3 reducer connection ahead of time.https://www.amazon.com/gp/product/B01M5BQAC5/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

The "Celestron Dielectric Star Diagonal 2" with Twist Lock" I just received I installed on my Celestron Nexstar 8SE. I have been using the 1.25 Diagonal and I am very impressed with the improvement. This is worth the investment.

I have the Celestron Evolution 8 telescope. It came with the 1.25" diagonal and it worked. I had been reading that the 2" would increase the viewing area (along with a 2" eyepiece) so I decided to take a gamble and I'm glad I did. Not only did it increase the viewing area, it made the images sharper. Again, don't know if it is the diagonal or the 2" Luminos eyepiece (31mm) but I am very happy with this upgrade.

This fit my Astro Tech AT115EDT perfectly.. I like the fact that it includes twist lock adapters for both 2” and 1.25” eyepieces. Basically it’s a complete package, with everything needed to fit a large variety of telescope.

Let me start by saying this is an excellent star diagonal with excellent retention performance on the twist lock rings for 1.25" -2" barrels. Solid construction and manufactured in Taiwan. Holds all my eyepieces from the heaviest to lightest with installation ease on a Celestron Nexstar 8SE.Why the 3 star you may wonder? Well, the SCT adapter ring that free floats and attaches to your telescope/ corrector/ reducer doesn't have deep enough threads! Full thread engagement is only exactly 1/2 turn onto the Celestron brand f/6.3 reducer, but has about 3 turns (if diagonal is threaded directly) to engage the back of the telescope. I had it come loose a few times (even with the eyepiece and diagonal leaning with a right bias), but luckily the threaded ring only clamps and free floats to clamp the diagonal when tightened. Very scary to have only half thread revolution to connect a very expensive Pentax eyepiece with this star diagonal and sometimes utilizing a 2x Barlow!The way I resolved this was to take the original factory 1.25" visual back from the 8SE and reuse that ring, since it has a full set of threads up to the edge that allows at least 3 full turns of thread engagement once installed on the 2" dielectric diagonal. The original threaded ring from the diagonal was reused on the visual back and offered a good 1.75 turns of engagement. Overall diameter of the knurled section is smaller, but I'd rather have the security and peace of mind with more than just half a set of threading engaged. If you're up for swapping, it was not exactly an easy task, since the threads on the SCT adapter ARE THREADLOCKED! I had to heat up the smaller end of the adapter (non-floating ring section with thinner knurling) that goes into the star diagonal to get the floating adapter ring free. Don't use tools with this, as it can and likely will mar the anodized aluminum finish.I hope that Celestron fixes this as this $200 diagonal should be better thought out about safe fitment conditions and full compatibility with more than just a half thread of security for some expensive and often times, heavy glass and aluminum optics attached to the other end. 3 stars for this oversight, on an otherwise excellent dielectric diagonal.