Thanks Hugh and Humayun,
It looks like I am on the slippery slope that is Astro Photography...even if it is with another photographers equipment. The learning curve looks steep.
My 12" Newtonian scope is a Flex Tube model.
www.bintel.com.au/Telescopes/Dobsonian/SkyWatcher-14--Synscan-GOTO-Dobsonian/767/productview.aspx
Will this allow focus to be achieved more easily if the OTA is shortened a little?