Hi There! Looks like a happy, well fed ball python!
Just a few suggestions:
--For more security you may want to cover the back of the aquarium with black paper (it also adds a nice look...I actually just spray painted the back when I used to have fish..do this outside without the python in there). If he ever has trouble eating, go ahead and do the two sides with black paper too...it will make him feel more secure.
--It's hard to tell from the pictures, but you definitely want identical hides on the hot and on the warm side. This is important so he doesn't have to choose between safety and temp.
--As another poster said, we should get a good look at the humidity in there. Aquariums are notoriously hard to keep humid. My suggestion would be to pick up a digital thermometer with a probe (for hot/cold side) and digital humidity gauge.
It looks pretty good for the most part, those are just some details that might help. Nice BP!
JonV