Hooking-up the "Spec" Loader to the Instanced Scale tool, I then bring-in a Color Corrector, adjusting the Master Levels to isolate the brightest Specular highlights.

Next, I drag-in a Highlight tool, fussing with the settings until I get something that looks pretty, un-checking the "Merge Over" control so I get just the "stars," and not the "stars" already merged onto the source image.

...Because I'd like to soften (Blur) the stars, just a little, before applying them.