A quick test I created trying to produce a realistic and interesting starry night sky in Blender. Some of the stars were made using the built-in star feature, and some of them were made using noise and voronoi textures.
Not bad, just a few minor things. The first being that you might want to add a very subtle gradient, second is that blue is a little extreme. Normally the blue areas are an illusion that are made by tons of very small distant stars in a close area, such as the band that makes up the milky way. A realistic effect might to be putting the milkyway in, btw.
In case that wasn’t very clear, less blue, more tiny stars, and a little fainter on the tiny ones.
looks great
but it cant be used for an animation because noise texture and star feature change randomly 
@ GraphiX, actually, there is a very subtle gradient. It’s very subtle 
And I’ll lessen the blue a bit, though my idea was that there would be tons of tiny, more distant stars filling them in. That’s why there are more visible stars in those areas.
@Idh1109, I know it can’t be, unfortunately. But the same could be done entirely with voronoi textures, I’m sure. I’ll try that next…