Such is my experience with taking moon pictures. All I ever got was hideous nebulous balls of white light. Then I realized what was going on. The camera doesn’t know that I am trying to take pictures of the moon. It thinks I’m trying to take pictures of a large black space with a small bright light in the middle. So it sets the shutter speed accordingly, trying to ‘see’ what is in that big dark space.
When I realized this I simply turned my shutter speed up as fast as it would go (1/4000 s) and zoomed in as close as I could.
I love the picture but now I feel like I need a longer zoom.