I read it back in the early 1990s. The magic was drawn from sunlight and moonlight. Magic drawn from star light was forbidden. Until, of course, someone challenged that. That’s about all I remember. I think it was a multi book series.
Another set of stories that use this concept is Zenna Henderson's Book of the People, and "The People: No Different Flesh"
The people are aliens who have 'gifts', so more Psi, less magic.
One of the gifts is to "Platt Twishers" This is using mind plus environment to lift and move things. Almost anyone can use sunlight. Using moonlight is harder, but has more power. Darkness and Storm can move mountains.