Unlike glow sticks and old school ceiling stars, the new generation strontium aluminate based stars can be recharged charged over and over. They will glow all night for many years. 

Strontium aluminate, the newest non toxic glow material, doesn't lose its ability to recharge easily. I've tested this from posters painted over 10 years ago like the Pleiades poster (2012) above, they're as bright as the day I painted them.
You’ll notice that your glow art and stars are brighter at the beginning of the night than just before dawn.
The difference in brightness happens because the light has been discharging all night and just needs to be recharged the next day. (If you can't wait you can blast it with a top up during the night.)