What I was looking for was to use it as a horizon. Sort of something you would see if you were on the surface of the moon. I have a very basic landscape that I'm going to texture with a lunar shader. I'm also planning on trying a starship design and would also like to put that on a starry background. So in the first case I would imagine that the star field would need to be hemisphereical. I hope that makes sense.
I've never used particle effects and have just started reading up on shaders. But from what I've read and seen this looks to be one of the coolest parts of rendering.
Seanoz thanks for the info about the book. I'll look into it.
Not really certified not really new!