JohnG, I use IP2.75 also and I have not seens these artifacts in previous images - I must have stuffed up the processing somehow on this occasion.
For autoguiding I am using Guidemaster v 1.3x, and yes, I can calibrate OK - that's how I measured my DEC backlash at a whopping 17.5seconds.
I guess I must just bite the bullet and get good at drift alignment....I do get confused with left, right, north south with the use of a reflector and refactor...I have read the instructions many times but always get confused when I am under the stars...was hoping a rough polar and guiding would be good enough. Guess I was wrong.
