Thank you for the feedback Lesley!
Here is the new version:
I don't quite know how to go on with this piece. I guess I have to make up my mind first about what is actually around the Orrery in order to do stuff like bounce lights and also attempting to render the materials.
Maybe I should phrase my question like that: When I have practised the stuff I intended to practise with a practise piece, should I keep going (even though that would mean "wasting" a lot of time with other things like rendering materials), or should I call it a day and go on to the next practise piece?
Have a great weekend, everyone!