709 BCE eclipse refines Earth's rotation and solar activity estimates

Researchers recalculated the total solar eclipse of 709 BCE after correcting the coordinates of the ancient Lu capital by about 8 km. The work yields a ΔT of 20,264–21,204 seconds and a possible earliest description of the solar corona, hinting at rising solar activity.

• Ancient Qufu's coordinates were off by roughly 8 km
• ΔT for the 709 BCE eclipse is estimated at 20,264–21,204 seconds
• A Hanshu passage may be one of the earliest corona descriptions
• The study was published in Astrophysical Journal Letters