starnet "It is very unlikely the 10 (or 20 or 30) second sub-exposures are exactly that, continuous exposures of that length. If the telescope does no tracking during the exposure, the image can move up to 15 arcseconds/second, depending on declination. Since a pixel is 2.44 arcseconds, that means up to 6 pixels/second, or 60 pixels for a 10 second exposure."
Do you believe the telescope is not tracking during the 10-second (or 20-s or 30-s) exposure? I assumed tracking was continuous. Apart from correction "nudge" between exposures I would assume that the stepper motors are being controlled (by dead reckoning following the 3-point "drift" alignment at enhancement start-up) throughout the imaging process not just between exposures? With only 2" aperture, exposures considerably less than 10 seconds would mean readout noise swallowing dim information just by lack of photon count per pixel.