Ovenpaa

Thank you all, I am now the proud owner of a 14" Orion Dobsonian, I have added a 450D with Backyard EOS and have the tracking software driven by my laptop so I am getting there. Now we just need to pack everything away and move and hopefully end of next month we will be in a new time zone with a dark sky enjoying the billions of stars around us.

Turning the tube down slightly gives a snug range of adjustment and once it is in the middle I can machine a stop ring.

The issue is the tube has a step of a slightly reduced diameter so the tube does not side through the focuser. This is easily resolved with a skim on the lathe to reduce the diameter.

Yes the dob is 2" and I have the T ring and a tube that screws in and fits the focuser. The issue is it is all about to be packed down ready to move to a new location/country end of the year and I suspect sourcing a different length tube will be time consuming

Is there a formula or guide to determining what length tube I need to enable a Canon 450D body to focus on a 14" Orion Dobsonian or is it a trial and error thing?

I ask because I have the Canon and tube off a 102 and would like to try it on the 14"

I think it is important to understand what you are letting yourself in for instead of jumping in with both feet. I think it was a similar number of years from meeting my wife to marrying her!

I have been lurking here for a while, in fact since 2015 so I thought it was time to say hello. I used to run a 4" Newtonian maybe 30 years ago however the ex ended up with that and I ended up in a large village and then in a smaller village so never truly dark skies. Now, at long last we are hopefully moving/retiring to a sparsely populated part of a small island in Denmark, so hopefully more time to peer at the sky and a lot less light pollution.

Right now I have no idea of what sort of system to aspire to other than astrophotography does rather appeal..

No doubt there will be questions along the way

David