Cheers Ray. PA is ok, within a few minutes. Not perfect, but good enough. I am getting RA drift of about 7"/min. The direction of the elongation changes over the frame. Top left is "down", centre is diagonal (/) roughly in the direction of RA.
I get the same issue with subs between 5s and 300s (tried 5s, 150s and 300s) and across all filters (oiii, sii, ha, l, r, g, b).
OAG was used in all of the 150s and 300s subs, no guiding used for either the good or bad 5s subs.
Uploaded
one of the uncalibrated 300s subs so the elongation / direction etc can be seen rather than just explained.
Guiding total RMS was about 0.63" over the 300s frames. Image sampling was 0.91"/px. In retrospect I needed to drop the min move and aggression, but the guiding wasn't overall terrible, and in fact, except for the elongation, I got some pretty good subs.