Do you ever wish your stars actually glimmered? Or that the evening sky had fireflys?
LEDs might just be the thing you need.
In this tutorial (thanks to the folks at Craft Gossip) you can learn how to attach LEDs to your embroidery. Please note: the tutorial is in Spanish.
Although the free pattern and example are on cloth, you can easily adapt this to needlepoint canvas.
Just be sure to leave open holes so the mesh can be expanded to fit the lights. If needed stitch around them later.