Looking for 12" tube rings

[Stefano Antonini]

Hi everyone,

I'm looking for ~12" inner diameter tube rings for my 10" newtonian. Does anyone have a pair to sell? The diameter of my OTA is 11.93", so something like this would be great:

 https://agenaastro.com/gso-telescope-tube-mounting-rings-303mm-11-93.html?srsltid=AfmBOoq3fY29H2GRFWAg7FJ7G5v6oSM9EbO-LY2I6lkju00MpsXTRHwy

Best,

Stefano

[Joel Lee]

Hi Stefano,

I have a pair of rings that came with my Skywatcher Quattro 250P that I don’t use. I can get you approximate measurements later today. Where are you located? I’m in Fremont and if we are close we can meet and test if they fit. 

CS,

Joel

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[Alex]

Is that scope for visual or imaging work? In the former case you can 3D print a decent pair (they might flex too much for the latter unless printed in industrial grade filament which might be more expensive than milling).

[Ted Hauter]

We need affordable rotatable tube rings to mount to Eq go to mounts.

On Tue, Nov 18, 2025, 3:03 PM Alex <alex.k...@gmail.com> wrote:

Is that scope for visual or imaging work? In the former case you can 3D print a decent pair (they might flex too much for the latter unless printed in industrial grade filament which might be more expensive than milling).

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[Stefano Antonini]

I need them for astrophotography, so they need to be rigid. I ordered a pair from agena astro, hopefully they fit. (And for as much as I love my 3d printer, I would not sleep well if I were hanging the 30 pounds of a 10" newtonian to a (beautifully) melted piece of plastic :) )

Stefano

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[Camerabooks.com Support]

Yeh, I had the same response to the 3D printed suggestion...

Tom

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[Camerabooks.com Support]

But before we do how about putting a large hose clamp inside a vinyl or plastic tube on the tube and leaving the rings slightly loose so the hose clamp can ride against the ring as the tube rotates. Inelegant for sure, but it works (got a scope with that exact solution a while back). 

Tom

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[Ted Hauter]

This can work. CN poster thank you.

Here is your 3D printing. Bolted curved stops on either side of the existing rings.

I do not know where to get large rings anymore. I'd get a 16 inch newt and do this if available. My old DX eq mount can take it 😅

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[Alex]

Hey Ted. That means a visual setup, right?
I think the GoTo should be OK with the 3D printed rings system flex. Because the latter would be less than the error caused by the optical axis of the Newt not coinciding with its OTA axis slightly. Thus, after the roll angle adjustment you would either want to re-align the GoTo anyway or just tolerate the error in the AFOV and adjust for it from the remote. Add to that the GoTo error caused by the not ideal and random orthogonality (dependent on the roll angle of the collimation axis)...

Thus, I would suggest 3D-printing such a ring system in some rigid enough filament (CarbonFiber PETG/ABS or better). Making it a bit beefier than aluminum mass.prod. one should be enough to make it totally reliable. I would add the 3-rd fixed on the OTA stopper ring to prevent the OTA from sliding down under the gravity when adjusting the roll.

I think I can help with the 3D design drafts, though not with the printing, as my BambuLab has only a 10x10" footprint (there is a multi-segmented design possible, but fewer pieces to join is always more reliable).
I would estimate the material cost of printing such a system for a 10" scope at around $20 + metal nuts/bolts of your choice for joints.

Upd: Just saw folks' concerns about the 3DP parts reliability. That's a misconception from the early 3DP days (I've been printing since 2014). I saw ABS parts printed for car and motorcycle frames taking hundreds of pounds dynamic forces. They reported to hold even better than injection molded OEM parts over years of (ab)use. It all depends on the proper design, material, and printing quality assessment. Then a bit of personal observance (if you see a crack starting, just analyze, redesign, and replace the next day).

[Alex]

I wonder why one would want a German EQ mount upgrade for a small visual Dob? The Portaball design is the ultimate perfection! Tracking? Add an EQ platform. GoTo? Overrated unless you have a physical disability. Otherwise, learn constellations and Telrad TPM method with the handheld app, or maybe get a PiFinder and a power brick.

[John Pierce]

On Wed, Nov 19, 2025 at 11:48 AM Alex <alex.k...@gmail.com> wrote:

I wonder why one would want a German EQ mount upgrade for a small visual Dob? The Portaball design is the ultimate perfection! Tracking? Add an EQ platform. ...

with a portaball scope, you can track by using a simple bearing axle at the equatorial angle, like 37 degrees around these parts. 

for instance, SCAC member Bill S built this creation about 10 years ago...

the compass and bubble level gets your polar alignment close enough, the drive axle angle can be adjusted for latitude, and the knob fine tunes the tracking speed.

It supports this homemade 6" ball+truss scope...

[Ted Hauter]

The accuracy on the stops at the tube rings will always be a little off. Low power views, or at least to start off until knowing which way the object is out of the field of view.

We are talking seated, tracking 16 inch views on a mount that holds a C14 (about 55 to 59 lbs. which is why celestron made the GCX and L version to better hold the 14 inch.) But I'm not so sure they are any better with that much weight on a gem. Basically this is killing the mount little by little but I think it is worth it. As long as balanced slightly off so weight is into the gears it should work.

The issue is the stops. Stops on both sides of the rings need to be bolted through the tube and that is a round surface, high precision work.  As long as bolted all around a full ringed Stop and a very wide spacing between with a huge D series plate, this looks feasible. 

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[Ted Hauter]

I should say weighted INTO the gear direction for backlash.

[Alex]

Thank you John. I've seen these designs too. Though that's the solution for avid ATMers. :) I'm talking about simple off the shelf solutions. Portaball works on any EQ platform with minimal modifications (just plop the stool on top and make it resist sliding with a rubber mat). But in just 1 day I have designed, 3D printed, and custom-tailored 3 identicall support pieces with precise ball-shaped friction surface for mine, attached them to the plywood piece base by 2 wood screws each, and it works flawlessly (even better than the OEM stool I think), including with the declination pushpin of that EQP fully functional (otherwise I could skip cutting the base board to the size too). Or I could simply cut a round hole in the EQP top board, but that could decrease its rigidity, and also make it less universal as a common tracker.

Ted, these stops are probably what I call "the third fixed ring" above? (the image is blurry) For the OTA sliding prevention when rolled with clamps off? I bet a full ring would be more beneficial as it could hold just on friction (no need drilling the OTA) and should distribute forces more evenly keeping the shape better. It will be engaged only when you carefully rolling the OTA in the losened primary rings, te latter should be good enough to hold it most of the time.

Also, it's an absolute nobrainer to make the precise match of the curvature for these OTA parts having a 3D printer at hand: just print a thin section first, check on the OTA, adjust the drawing, print again, repeat until 100% satisfied with the fit, print the final product. There is a caveat, though. The thermal expansion is different. Thus some tension mechanism would be still required.

[Ted Hauter]

Hi Alex,  

Thank you for the support.

I hope all can be successful at what it is they want.

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