I did this research while serving at Taranhai in Anieth. I was there as an astronomy student for many years. I was also an astronomer on Earth, so I was able to better understand ancient ideas. See the book, Tales of Anieth: Thorn, for my story.
THE ORIGINS OF ASTRONOMY
ANCIENT SKIES & AXIAL PRECESSION
THE SERPENT & THE TREE
ANCIENT EUROPEAN SKIES
THE GIRDLE OF ARIANRHOD
NUMBERS & ANCIENT ASTRONOMY
STELLAR CALENDARS
STELLAR OBSERVATORIES
CONSTELLATIONS