[Kokatha man]

Hi again omnivorr - our mothers must have used the same cookbook!

All this is very hard just using words: if we could on-line make continuous sketches and point etc it'd be solved in a flash!?!

Reading your last paragraph I understand the x axis as being "polar aligned" (ie parallel to the Earth's axis of rotation) but am not 100% about the "pivot axis of tube now verticle, at end of fork pivotted from the x axis"

From my perspective, if saying the above you are saying "pivot axis of tube which is at the end of fork pivotted from the x axis is perpendicular (at right angles) to this x axis (ie it rotates or spins around a projection or imaginary extension of this x axis) then you have your EQ set-up and the object pointed at will be able to be tracked as it moves from east to west.

Will leave you to ponder my (imagined) re-phrasing of your statement - I'll sign off for the night in case The Thought Police come knocking.....have no idea who would possibly sick 'em onto me though!?!