Speaker
Description
Some of the participants might be preparing scientific measurements, experiments, or campaigns for the total solar eclipses this August or/and next August. We have good reason for such campaigns, as total solar eclipses have been not only astronomical spectacles but also astrophysical laboratories throughout human history. These astronomical spectacles serve as spot references for the variability of the solar atmosphere, the coronal dynamics, the solar radius, and the Earth's rotation speed -- even without expensive spacecrafts. Looking back the human history, even on a datable basis, reported total solar eclipses have been confirmed since 709 BCE and extend their chronology centuries or even millennia beyond the coverage of the space age. Their chronological coverage is even longer than that of instrumental sunspot observations (since 1607) and particularly unique for the direct solar observations. Some of such eclipse records involve indications of morphology of the coronal structure and can be used as spot references for the solar-cycle phases. These records offer valuable spot reference for the space climatology even before the telescopic observations. This presentation aims at showing some case studies on their use before the space age, especially in terms of our analyses on the coronal morphology and the latitudinal extents of the streamerbelts. Particular emphases are placed on those in the grand solar minima and pre-telescopic ages. We examine their chronology and case studies back to 709 BCE on the basis of original historical records (e.g., Hayakawa et al., 2025, ApJL, 995, L1), in comparison with Usoskin et al.'s recent radiocarbon-based solar-cycle reconstructions with an annual resolution. Our results serve as independent reference to confirm and examine the recent solar cycle reconstructions for the last three millennia.