Focuser questions - Setting up focuser for RC 12

[skybadger]

I am looking to understand my options for putting a more weight capable focuser on the back of my homemade 12" RC.

I  am currently using a 2" Revelation crayford type focuser. Having upgraded my camera to a new 2nd hand Atik11, that focuser just cant hold the weight. So I need a new focuser. 

That focuser has a 60mm thread on the back to fasten it to the scope  focuser plate which I made on the lathe.

My question is really about what size interface or extension pieces are commonly available commercially or through materials supplies for me to manufacture ? Which drives me to picking a standard size of fittings. 

If I put a Baader steel track on there, that focuser has a 90mm diameter dovetail that can fit on a 68mm thread but the Lyra RC scopes often use 100mm diameter extension tubes and there aren't many of them about. 

Is there a source of extension tubes I can adopt that are fairly common ? Are there other focusers that also fit the bill? If there aren't, my thinking is that I'll have to make them and that's a chunk of metal to turn, 90mm being an unusual tube size too. 

Has anyone fit a refractor focuser (with extension tubes to take the longer focuser tube) or are there reasons not to do that ? I reckon I have about 180mm of focus depth available to fit this in, even when using a reducer. 

 

 

 

 

[Davehux]

The StellaLyra 6&8" RCs use 90mm x 1 extension rings. Available from FLO in 25mm and 50mm

https://www.firstlightoptics.com/adapters/stellalyra-m90-50mm-extension-for-6-8-rc-cc.html