Thank you Rowland, Greg, Ivo, all.
My initial sequence is using mostly what Louie (Atalas)
has setout in one of his
online tutorials.
He suggests first gentle curves and levels then a more
aggressive one.
The thing that I cannot really understand is what shape curve
to apply according to the subject matter.

Obviously, my effort has made the tonal range fairly bland
and not very contrasty, and all of your efforts look way better
with that.
My aggressive curve is typically the 'quickmega' shape in Nebulosity,
fairly steep down near the black.

I love the noise reduction in all of the attempts, way better and smoother

This gives me a lot of hope with processing my backlog of 'best ofs'.
I wish I had given you guys a better looking galaxy to try out on.
She certainly is an ugly galaxy

Imagine being told you live in
an ugly galaxy.
Thank you guys so much for the efforts
Steve