Thanks for asking and for your interest in the processing steps.
At the time of Deconvolution the image is been showed with an automatic STF applied which is good to see how Deconvolution affects the image in general or the background but do not allow to see very little changes in bright areas.
Note that I have used STF in all process until Histogram transformation.
The next screen shot has deactivated the STF and is more noticeable the change made by Deconvolution in the core of the galaxy and the stars.
You are right that Deconvolution is very time consuming, at least for me, but in some images worth the time. Deconvolution with preview:
The result of the process in the complete image and in a preview are different, but even that you can approach your result using a preview (maybe 1/4 of the image) and then get the final approximation in the complete image.
In this case I have used a preview of the galaxy and only had to adjust a little the deringing parameters for the final image.
Tip: you can try in a very small (and fast) preview of some stars and learn how Global dark parameter in Deringing affect it, and then you will know how to adjust it in the final image. "the noise is gone!!!"
Unfortunately not, the noise is still there.
After deconvolution come Histograms Transformation.
First remember that at this time you have the image with and STF applied which means that if you deactivate it will see the image almost completely black.
With HT I have stretched the image to a point where the noise is not as evident as the noise that we were seen with the STF.
This is the real change after applying HT:
PS: Do not despair! It's a hobby