| Abstrakt: |
We obtain a narrower and more reliable range of the delay of Earth’s rotation, ΔT, than those obtained before. At the same time, we determine the observation sites of these eclipses in the early seventh century. The eclipses are the one on AD 616 May 21 recorded in the history book Suíshū of the Suí dynasty, and the one on AD 628 April 10 recorded in the first official Japanese history book Nihon Shoki (also called as Nihongi). Our method of analysis is to express multiple observations simultaneously on the “Sôma” diagram in which the ordinate is ΔTand the abscissa is the correction to the coefficient of the lunar tidal term. In order to increase the reliability of the present result, we analyze several solar eclipses and an occultation of Mars during the period from the fifth century to the end of the seventh century. These analyses show the short-term variations of ΔToff the smoothed spline curves of Stephenson, Morrison, and Hohenkerk (2016, Proc. R. Soc. A, 472, 20160404). |
