Dick,
Change of topic -- since I don't know how to message you directly. This is about stacking.

I have bookmarked some helpful guidance that you have given to this forum on calibration and stacking.
Does this imply that you find this capability useful? Or are you doing the calibration and stacking yourself to get better image processing results? (Bob Denny seems to imply in at least one case that automatic calibration and stacking is most useful for those doing science-related imaging.)
Warmly,
Roger
Note: I see that your retired from MITRE. It is a big company. Did you know Bob Everett who recently died or perhaps John Quilty?