>I realized I was too aggressive when processing M31. I reprocessed it
>from scratch and tried not to over enhance it. I used wavelet transform
>in PixInsight LE to reduce noise and to enhance the inter-arm dark >clouds.
>Thanks to Juan for tricks about wavelets.
>Again, the link is
>
http://www.ifa.hawaii.edu/~wang/gallery/picutres/m31-2004.htm
It is a beauty! Congratulations for the new processing. Now it looks much better. There is nothing I can suggest to improve it.