M31 - Andromeda Galaxy through a 6 inches refractor

This video is composed from the 200 subframes of 30 seconds each one taken to be stacked into a final image. It is very clear that the Sky-Watcher EQ6 equatorial mount has a periodic error in declination (north-south movement) and drifts a bit in right ascension due to a lack of equilibrium in the setup. Final stacked image may be found at http://www.awesky.com/Deep+Sky/Messier/M31+through+a+6+inches+refractor/