rotating rings Vs rotatimg scope

I'm thinking about converting my 16" sonotube neut on a gem to an aluminum tube with truss to a secondary cage. I'm leaning toward building rotating rings so the whole scope can rotate ... but it would probably be easier just to rotate the secondary cage ... but then if alignment is not perfectly centered with the primary this may cause a headache.

Any thoughts on these two options.

Dan

My opinion is it is a collimation headache to rotate the upper ring/cage on a fast F/ratio scope you assemble each time. When Sky Valley Scopes was making complete telescopes, they did a neat rotating OTA design that really should have been more popular than it probably was, IMO.

Dan, a year or so ago I made a 12.5" f/5 dob that was patterened after a Starmaster with 4 truss tubes. I made a square upper tube plate to attach the tubes to, then attached a round secondary cage. In the inner cage ring, next to the square plate, I cut two 45* arcs with a router. Then I put two 1/4-20 bolts and wing nuts through the plate and inner ring so that the wing nuts could be loosened and then the cage could be rotated the 45* allowed by the arcs. It was aligned so that the eyepiece would rotate from almost parallel to the ground to almost vertical.
It worked very well and I hade no problems maintaining collimation.
Sorry I don't have pics anymore, the files got deleted somehow.

Walt