Because you require long exposures for each filter, do you have problems of not having consistent sky transparency in order to achieve identical superimposition of images?
Eamonn, all my images are taken over several nights, the weather has not been too good for me (on Sunday it was 100% cloudy here and 100% clear over in Dave Grennans, and only 20mins drive), to capture all the data for one image in one night, but that is life.
So to answer your question, I haven't noticed.
Well done Gary. How do you combine the narrowband images? Do you combine the raw images as RGB or processed images as RGB? Never tried this so curious to know.
Kieran,
I process the images a little bit in Images Plus, and then combine them in CS2, then I'll use Images Plus, CS2 and MaxIm DL to do more processing, depending what needs to be done.
  