SkyWatcher mounting rings on Orion XT10i

[Zodiacal_Light]

Hi all

I have recently got myself a SkyWatcher EQ6 Syntrek mount to go with my Orion XT10i telescope. I was of course quite excited when it arrived, but there was only one problem. The tube rings that I ordered was too small. And this after the sales person assured me that the rings would fit.

I measured the inner diameter of the rings and it looks like it is about 288mm whereas the outside diameter of the tube is about 1cm larger. At first I though that maybe they should be this tight to secure the telescope, but after I saw a scratch on the tube I knew something is wrong.

Another problem is that the store only stocks SkyWatcher rings and it's the only shop that I know of here that sells mounting rings. They also have rings for 12" telescopes, but I'm afraid that they will be too large for my 10". The ones I ordered are classified as 10" telescope rings. I guess this only applies to the SkyWatcher telescopes.

Now my question is will I be able to modify the current rings to fit or should I return them and ask the shop if they can import Orion type rings that will fit the XT10i which may cost even more?

[Phil Fargaze]

I have exactly the same scope and had the same problem. I found that the skywatcher rings were too short in circumference. What I did in the end was to make up some spacers and put them in place as seen in the picture. It seems to work fine. The other thing I had to do was to open out the existing rings to ensure an acccurate fit around the slightly larger diameter. This was done by carefully applied pressure, which was done by having one end of the ring held. Then the bottom of the ring pressing on a solid surface and then pulling out on the other end. As I mention, care must be taken to not over stress the material because I am not sure how brittle it is but I did manage to open the ring out to the required size. This would need to be done on both halves.

[Zodiacal_Light]

Thanks Phil, that seems like a good idea. What tools did you use to make the spacers? Could a wooden spacer also work or must it be made of metal?

[Phil Fargaze]

It is a bit of a tricky problem because of the expanders have to be offset and not straight. I managed to be able to do them at work. My method of making them was to get two aluminium blocks and weld them together, with a slight crank so as to follow the radius. The ends were drilled and I used some suitable M6 nuts and bolts to connect to the rings.

I would doubt if wood could hold up because it could likely crack along the grain at some point.

There`s a chance that if I still have some of the same material at work, I could knock up another couple for you. I would have to check tomorrow.

[Zodiacal_Light]

Would it not work if a bolt was threaded through the middle of a wooden spacer so as to make the spacer able to bend along with the radius of the tube?

So in other words the spacer would consist of 2 blocks with a bolt to hold them together and also make it able to bend. That should relieve some of the stress on the spacer I believe.

Thanks for the offer to make me some spacers, but I'm located in South Africa . The reason I would like to try wood is because I have someone that is good at woodwork.

[Phil Fargaze]

Ah... your not very local, I`m in snowy London! Maybe your best bet would be to try the wooden spacers, seeing as you know a good wood worker. I don`t know much about wood but I guess that some type of hard wood could be quite strong.

It`s certainly worth a try.

Don`t forget to make the rings a little short at the other end (10mm-15mm) so that there is space for them to close up tight around the tube but not actually touch.

[Zodiacal_Light]

What do you mean by a little short at the other end? Should the spacer just be long enough to leave a 10mm-15mm gap at the other end?

[Phil Fargaze]

Yes, sorry. Once the spacer is fitted and the rings are put around the tube, it would be best if the spacer was not too long. You might have realised that already but I thought I would mention it just to be sure. The effective lenth of my spacers are 45mm.

[Zodiacal_Light]

Ok thanks Phil. I will only have access to the telescope in about 2 weeks time as it's stored at my parents house. I will give an update once I've tried the modification.

[Zodiacal_Light]

I've managed to get the rings sorted out. It seems to fit the tube quite well, but the only problem now is that it's cloudy. Here is a pic of the spacers I used:

http://imgur.com/LIEPV.jpg

Thanks again Phil for your help. I appreciate it.

[Phil Fargaze]

Excellent solution! I hope the clouds clear soon for you!