Analyses of Early Sunspot Records by Jean Tarde (1615 – 1617) and Jan Smogulecki (1621 – 1625)

Abstract Jean Tarde and Jan Smogulecki carried out sunspot observations in the 1610s 1620s at dawn of telescopic era. We analysed their original observational records to revise sunspot-group numbers existing database. In this study, we provide a new counting as basis for future scientific discussions. Furthermore, compared Smogulecki’s with those Scheiner Schönberger on same observation days. also detected big group 2 – 3 February 1622 drawings estimated its area be approximately 1600 millionths solar disc. addition, measured positions Tarde’s construct butterfly diagram early period.