Some Vixen threads:
Standard drawtube, as already mentioned is M60 x 0.75
Older focal reducers- back side attaching to camera or diagonal: M43 x 0.75
Some step-down adapters and rotating rings use M53 x 0.75
Having an adapter made right now to go from an older Vixen focal reducer to a T2, and having it rotate as well for camera orientation. Will do pictures when Hugh finishes
