Speaker
Description
Recovering historical solar and geomagnetic observations is essential for extending the temporal baseline of Space Climate research. A significant amount of valuable material remains scattered across solitary archives or published in sources that are largely inaccessible to the research community. In this contribution, we present recent progress in identifying, analyzing, and contextualizing several sets of historical records relevant to long-term solar variability.
First, we revisit early sunspot observations made in Spain. These include the records of Diego Torres Villarroel during 1744, the observations of Lorenzo Hervás Panduro in 1791, and several additional isolated observations that help to fill existing gaps. We also highlight a rarely cited 1921 report by F. Damián y Manté describing a striking hexagonal sunspot, an unusual morphology that attracted contemporary scientific interest.
Second, we survey early observations of solar flares, emphasizing both their historical evolution and their potential contribution to Space Climate reconstructions. Special attention is given to the exceptional observation made by J. Birmingham on 6–7 May 1871, which may correspond to a recurrent white-light flare, an event of considerable interest for constraining extreme solar activity in the 19th century.
Third, we examine several cases of historical auroral sightings. These include reports associated with the 1588 expedition of the “Invincible Armada,” as well as documented observations by Fathers Feijóo and Isla during the 18th century. Additional noteworthy events are discussed for their relevance to understanding past geomagnetic disturbances at mid and low latitudes.
Together, these findings demonstrate the scientific value of re-examining historical sources. Such records, once properly analyzed and integrated, provide unique insights into long-term solar behavior, help refine reconstructions of past space weather and space climate conditions, and contribute to a more complete understanding of extreme solar- terrestrial phenomena.