Case file · Cosmic event
Goryeo sunspot records
The court astronomers of Goryeo, at Gaegyeong (Kaesong), noted dark spots on the sun from 1151 on (one 'as big as a hen's egg'), a series later used by solar physicists.
1151 CE · 37.98, 126.55 · status: official
The account
The Goryeosa, compiled in 1451, preserves dozens of naked-eye sunspot sightings and many aurora records. Together with Chinese and Japanese logs they help reconstruct solar activity centuries before telescopes.