I have a concrete pier, the base being a random hole in the ground about 0.6m deep and 1m dia.
I often wonder why ppl make huge concrete bases of 1m deep or larger, but have been lately thinking perhaps this is a good thing
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I have found I that my polar alignment drifts out by some 20 arc/mins over a period of 4 months or so and am wondering why.
Doesnt sound a lot, but guiding gets progressively worse over this period (at 2250mm FL) and then snaps back to perfect after a retune.
The concrete is (past about 100m of soil) into shale thats seems stable. Im wondering if this drift is due to a small shifting base, or a fundamental ground shift depending say on moisture due to changes in weather?. Does the ground level generally, anywhere, change over time with the weather, and render any pier base construction mute anyway?.
Im not fussed with periodic polar alignment, but the need is a puzzle.