I did this set 2 nights ago while also getting RGB data on NGC5128.
That RGB set was 7.5 sec subs cooled to 10C (with 7.5sec darks)
This NGC 6744 set was only 5 sec subs at 10C.
I forgot to do the 5 sec darks for this set and processed this morning
oblivious to the fact that it needed 5 sec darks at 10C.
The first result is using the wrong darks (7.5s 10c darks on a 5sec 10c set)
The second result is with a set of 5sec darks at 10c from a 28th of March
session.
The second one has no trace of the gradients and herringbone noise and
survived a bit of sharpening.
Steve