Raymo, this reflection nebula is very dim, lit by the star Rigel. You have to get yourself out to a relatively dark sky to have any chance of capturing it. Don't know why you couldn't see it with essentially the same amount of exposure, though at 50mm it would have been small. There were a few taken at f4.5 amongst the 32 subs only because I forgot to stop down after refocusing but the majority were at f 5.6. It may have been in your processing that restricted the witch from displaying her features, your blacks certainly can't afford to be clipped. You could hardly see her in a single sub and only because I knew what to look for. To the untrained eye she would be invisable. Not until I stacked the 32 subs did she reveal herself and I would have liked to have taken a lot more, had the wind not been a problem.
Try reprocessing your old data differently, maybe stretch it a bit more but that will be difficult with only 6 subs. Noise will then become your enemy.
