Posted by Callum Potter at 17:45 on 2012 Sep 09
Sorry if its stating the obvious, but you should be stacking calibrated frames – ie, frames corrected with darks, flats and biases (from the night the images were made).Then there should be no problem stacking from different nights.Good stacking software should align even if there is some misaligment of frames.I have tended to use IRIS which also works with 32 bit integer data – a point Graham makes well.Callum