Tube ring sizes

[MylesGibson]

9 hours ago, Philip R said:

 

@omo has suggested to contact Orion Optics which is an option. I would also get in contact with SCTelescopes and see what he would advise, before attempting anything at this stage. It is a triicky one to answer, unless you have an engineering or optical/mechanical engineering background, which I do not have. He has done restoration work on the late Sir Patrick Moore's telescopes and others.

Out of interest @MylesGibson what is the OTA's weight? - I feel that using Jubilee hose rings, (as I have done with my 're-modded' ETX105), may not be substantial enough to support the weight of your 'scope. However, if you do decide to go the Jubilee hose rings route, you will need to purchase some felt, cork or neoprene strips to prevent them from scratching the tube.

I'll look at contacting these places. I do have an engineering background...... Although it is in electronics, not mechanical! 

I'm not sure of the OTA's weight. I havent taken it off the mount yet to weigh it. It doesn't feel too heavy in all honesty. Unsure how easy it would be to strip down though, seems to be built differently to some modern scopes. Saying that, I haven't had a serious look yet.

[johninderby]

The expensive solution. Telescope Express sells a lot of different tube rings including custom sizes but they can be £££££

https://www.teleskop-express.de/shop/index.php/language/en/cat/c266_Rohrschellen.html

Edited May 19, 2020 by johninderby

[RT65CB-SWL]

Hi @MylesGibson.

If you can post some images of your 'scope, then it would give us a idea on how to proceed to the next level. I did have look at various online images before my reply, but they were not showing a lot, especially around the area of fork mounting. 

Another place you could try is: Beacon Hill Telescopes. He is based in Lincolnshire. He makes bespoke items for astronomy use and has made a few accessories for me in the past.

Have you any local engineering workshops nearby. Another invaluable source. I suppose I was fortunate to find one near me that was prepared to make a replacement backplate for my ETX105. It was a tad pricey for a 'one-off'. I was given an quote/estimate, but not to far off from it. I did not want to see a good OTA end up as another 'landfill' statistic. Like you, finding tube rings to fit was the next problem, (either to big or to small), as it was not a standard size and did not wish to drill and tap the OTA for the dovetail bar.

Keep this topic going with your progress.

[MylesGibson]

1 hour ago, Philip R said:

If you can post some images of your 'scope, then it would give us a idea on how to proceed to the next level. I did have look at various online images before my reply, but they were not showing a lot, especially around the area of fork mounting. 

Another place you could try is: Beacon Hill Telescopes. He is based in Lincolnshire. He makes bespoke items for astronomy use and has made a few accessories for me in the past.

Have you any local engineering workshops nearby. Another invaluable source. I suppose I was fortunate to find one near me that was prepared to make a replacement backplate for my ETX105. It was a tad pricey for a 'one-off'. I was given an quote/estimate, but not to far off from it. I did not want to see a good OTA end up as another 'landfill' statistic. Like you, finding tube rings to fit was the next problem, (either to big or to small), as it was not a standard size and did not wish to drill and tap the OTA for the dovetail bar.

Keep this topic going with your progress.

The image on the previous page is the scope that I was gifted. If you need more images, I can take some tonight while setting up my main scope. 

I have a few engineering friends so once the lockdown is over, I'll have a word with them to get some input there.