I've got a piece of artwork with a gradient background with no banding. On top of the background are a moon and stars I've I've colored yellow and used "color dodge" to blend over the background. For some reason, the moon has a banding/pixellation problem. I'm not sure how to fix it. I've tried rasterizing, but that just flattened it back into opaque yellow. I don't know how to make it look smooth. The other objects with opacity are not doing the same thing when placed over the gradient.

You can see the sun (color: red, blend mode: overlay) is blending nice and smooth, but the moon looks pixellated.

How can I make the gradient in the moon look smooth like the rest of the artwork?