There's too many tiny stars.It just looks like a layer of noise. Maybe just drop the levels to make it dark enough so most of them fade out without losing the main stars. And there's a large "rift" of vacant space down the centre.
That is because it is from this piece: [link] and I knew that I won't need much stars there. The small stars look like noise but when you do the piece with all the adjustments during the process they get really better