I sprayed the ceiling using an portable Wagner paint sprayer. After two coats, I trimmed all the strands, leaving about 3-4mm of excess sticking out. The excess is so if I ever want to paint the ceiling again, I can just snip the painted end of the string off and the light will shine again. It would look better to snip it flush, but then I don't think you could repaint the ceiling...
a much easier alternative is to use glow-in-the-dark stars you affix to the ceiling with poster glue. or just straight glow-in-the-dark paint. you'll get the star effect for awhile, then they'll gently fade as you fall asleep.