Thanks Mike.
Yeah, that 2nd one was a strange one. It was taken through cloud and I had to ditch some of the frames coz they were too dark.
It's funny how the difference in transparency can have an impact on the colour of an image.
You're right about the image scale, but it's like aperture... now I want more. Gimme gimme
Just have to make sure the seeing's up to ext tubes etc
Thanks for the feedback everyone