I've been planning this beast since it cropped up in white dwarf. Still haven't seen one done like this. It's going to take an age. But this is the plan for the top oracle!
All from the airbrush.
1: base of gold over brown
2: layer of Vallejo angel blue
3: layer of French blue radiating from the central sun.
4: construct planet orbits and finish with a light layer of light sea blue.
Then paint all the details, planets etc.
then do all the highlights again and finish with edging in white and turquoise.
Just writing it down is tiring. At the moment I'm on stage 4. :)