Okay, I redid the stacking this evening. I've updated the OP with the new file, but here it is also (33 MB zip [inside is a 109 MB FTS file]):
https://dl.dropboxusercontent.com/u/...ationalFTS.zip
Following the advice above, I adopted the following procedure in DSS:
Guiding principle for Startools pre-import file preparation = minimize manipulation of images in DSS – keep them as ‘virgin’ as possible
Register Settings
Star detection = aim for ~50 stars, no noise reduction by median filter
No automatic detection of hot pixels
Stacking Parameters
Result = standard (or custom), no alignment of RGB channels, no drizzle (except small custom areas)
Light = median, no background calibration
Dark = median Kappa-Sigma clipping, no hot pixel detection, no dark optimization
Flat = median, Bias = median, Alignment = Automatic
No intermediate files, No cosmetic post calibration
Other
No post-processing in DSS, export as rational 32-bit FTS
Attached image shows what the pre-stacking settings look like.
Ivo, I imported this into Startools and have started mucking about. It is already looking better, I think, but any advice would be welcomed!