[LewisM]

Attached is a sample of stars near the centre of a single unprocessed 20 minute guided sub I took recently (out of focus, as were the ENTIRE 2.5 hours worseluck, but using this to draw some conclusions). Magnified 200%

Does this slight elongation appear to be polar alignment issues, flexure, camera tilt?

20 mins single exposure, using a Lodestar through an f/9 guidescope (secured to scope with solid rings, not guidescope rings). Imaging scope Vixen FL102S, reduced. SXVR-M25C camera. All screwed components in the imaging train - NO compression rings etc. Mount is a Vixen GPD2 using a Skywatcher EQ5 GOTO upgrade kit (that I tuned). Seeing was 9/10, nil wind.