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Coming along marvellously! A great result and fantastic for the circumstances.
There's no sign of field rotation there. Stars look great. If the polar alignment is off along the same hour angle as where you are photographing, then you not only get nasty field rotation, your guiding can get lost in the dec backlash. Conversely, if by good luck your polar axis is off along an hour angle that is at 90 degrees to where you are photographing, then at least for an hour or so you get no field rotation and consistent guiding. Perhaps the pier moved in a direction that was harmless or even helpful given where you were photographing. (With our fork mount, we intentionally put the polar axis 0.04 deg west of the SCP. That gives excellent behaviour when photographing say 60 deg either side of the meridian. And 2.5 tonnes of steel reinforced concrete in solid rock makes it stay put!)
Best,
Mike
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