a33
Specialised Contributor
- Joined
- Sep 24, 2009
- Messages
- 1,254
- Reaction score
- 720
- Points
- 113
- Age
- 63
- My Satellite Setup
-
XSAT410
Rebox RE-9000
- My Location
- The Netherlands
To get a 180 degree movement the actuator arm would have to be on top of the polar bearing.
Exactly. That would be the factual theoretical maximum, to which I did my calculations.
And I described the outcome of the calculation in relation to that 180 degrees/zero-position, as I indicated clearly.
Nothing wrong with that.
And no ~15% off (or whatever percentage, and however calculated).
The fact that the zero-retraction (and the 180-extension) can not really be reached in actual practise, does not alter the calculated angles.
So all this just distracts attention from the fact, that you can choose your zone of highest accuracy, by choosing the ratio of actuator fixing point distances.
And that choice also affects the accuracy for the more extended actuator zone, so it looks to me that it could be worth consideration, what ratio you choose. The effect, of course, is not huge. But the effect is there.
Could be, of course, that no-one ever considered the matter, in practise?
Could be that everybody only focussed on actuator length... (which, of course, also adds accuracy, when you in fact use the extra length by using new fixing points), but without consideration of the mounting distances ratio?
A33
Edit: few textual improvements.
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