[muletopia (Chris)]

Learned folk,
I have an hour of 5 minute shots of Helix. Gain 0 offset 125 qhy8l

I have a matching set of darks,that have been debayered then stacked to make a master dark.
When stacking the debayerd shots in Nebulosity without the darks used a recognisable image emerges.
If the shots are preprocessed and then stacked all trace of Helix vanishes.


I have used preprocess shots on other images with good results. ,my M55 image on this forum seems OK


I presume I doing (not doing) something wrong.
I hope there is a simple reason for this problem, any help would be much appreciated.


Cheers
Chris