Use a tiled starfield texture, or paint one. Tons of tutorials out there. https://www.google.com/search?site=&tbm=isch&source=hp&q=tutorial+starfield&oq=tutorial+starfield Use incandescence to make the sphere fully bright.…
Saw this earlier, searching Google for "starfield tutorial maya". Did you try a few searches? Seems like you haven't tried looking... http://thefulldomeblog.com/2013/07/03/creating-a-star-field/