Medieval society in our world had a pretty good understanding of astronomy as it was important for most activities (determining seasons without calendars, navigation without a compass etc.). GG is set in the early modern period for the most part and the countess from Homaspernia wears glasses, so lenses have been invented->telescopes->better astronomy. Combine that with magically enhanced senses and yep, they definitely understand stars better than we did back then, and probably understand space itself.