I have an AT-10RC that I bought used earlier this year. It came with a Feathertouch 3" focuser with 1.5" of travel. I am finding it a bit of a hassle when I switch between visual and photography on it, because I have to swap out the extension tubes (adding an inch or two for photographic use). I was looking at getting a longer travel 3" Feathertouch, but it appears that the outer diameter of the draw tube is just a hair bigger than the ID of the opening in the primary of the OTA, and would hit it when racked all the way in. A 2.5" one would definitely fit, though.
My question is, how much field of view would I lose in dropping down to a 2.5" focuser on that OTA, compared to the current 3" one?
Is there another option for making it so I don't have to swap extension tubes all the time? Would a Moonlight focuser have a slightly smaller OD draw tube?