A Comment on the Solar Activity Level in 1791 by Lorenzo Hervás y Panduro

Abstract

Past solar activity is of great interest for astrophysical and geophysical studies. Systematic searches over the last four centuries have detailed the evolution of the solar cycle. Brief comments on solar activity for periods with sparse records, such as the year 1791, are crucial. Lorenzo Hervás y Panduro, a Jesuit intellectual, noted in his 1793 book that sunspots were seen almost daily from 1791 January 1 to April 20. This would suggest a solar activity level estimated at a sunspot number of around 70.