Speaker
Description
Understanding long-term solar activity is key for advancing our knowledge of the solar dynamo and improving space climate forecasting capabilities. In this contribution, we present a comprehensive revision of sunspot records from two key periods: the early telescopic era and the decades following the Maunder Minimum.
First, we reanalyze Christoph Scheiner’s observations from Rosa Ursina and Prodomus, correcting errors such as misinterpretations in current databases. Our new group counts clarify the shape of the solar cycle in the 1620s and reduce its maximum amplitude by 20%.
Second, we revise records by Johann Leonhard Rost and Sebastian Alischer, identifying that previous datasets often confused individual spots with groups. This led to overestimated activity levels during Solar Cycles −3 and −4. Our corrected data suggest a more gradual recovery from the Maunder Minimum, in agreement with proxy-based reconstructions (e.g., cosmogenic isotopes).
