The Rosette was my first try with masked stretching using Pixinsight. My use of starmask is pretty limited and it shows! I am working now to try to get rid of the halo's. It was also my first attempt to shrink the stars using PI. Still learning but I'll get there. Here is another one I am working on.
forum: Astronomy & Celestial
That looks fantastic! Those stars look great.
Here's what I do to shrink the stars in PI:
1) Use the "star mask" to generate the mask and then apply it to my image.
2) Then use "MorphologicalTransformation" -- In the MorphologicalTransformation window set the size to "5 (25 elements)" and it should show you a 5x5 grid to the left. There are some icons just below the "Size" and "Way" pull-downs and you wan to find the icon that looks like a circle (2nd from left in the 2nd row of icons.)
3) Then go to the top section of that same window and reduce the "Amount" slider (it's set to 1.0 by default which means 100% and that's too much... back it off to about half (.50) and try it by applying it to the image (you might end up un-doing it and trying a little more or a little less). It does a nice job of shrinking the stars.
When you're shrinking stars then you're already at the point in your workflow which is more art than science... so the "right amount" is whatever you think looks good...
All the other defaults tend to be fine.