Combination of Apophysis and various filters in PSP.
Actually what makes this interesting to me is this:
It is the first blank screen Apo I've ever done. Well at least the first one I really liked. The two large "Gemini" type planet looking things were what inspired the idea of a "Space" scene. I've been reading every tip and trick I can find lately and I think, maybe, all my digging has paid off.