Hope you don’t mind me making a couple of suggestions?
Am I correct in saying that you sharpened the image?
If so, try a smaller radius next time (between 1 and 3).
Also, select a region which excludes the edge of the limb on the right side of the moon and feather it.
Due to the contrast involved, the sharpening creates a very sharp white edge to the moon’s limb.
Also, try “smart sharpen” rather than “unsharp mask”.