One of the early sunspot observers of the sunspots using a telescope was Galileo Galilei. Here, we analyse his original manuscripts, which were not mentioned in the Hoyt and Schatten database of the sunspot group numbers. Handwritten documents contains 107 drawings of the solar disc in 1612 and 1613. Several drawings were later printed in the book Istoria published in 1613. Another source of data on sunspots on the eve of Maunder minimum are the drawings in the 1630s made by Pierre Gassendi. First of all, these observations intrigue the solar community by the fact that even before the start of the Maunder minimum the spots tend to appear in the southern hemisphere. We present the preliminary results on the extraction of the number of groups, their heliographic positions and area. We also discuss discrepancies between manuscripts and published books.
Original languageEnglish
StatePublished - 2018
Event30-я Генеральная ассамблея Международного астрономического союза - Вена, Austria
Duration: 20 Aug 201831 Aug 2018
https://astronomy2018.univie.ac.at/home/

Conference

Conference30-я Генеральная ассамблея Международного астрономического союза
Country/TerritoryAustria
CityВена
Period20/08/1831/08/18
Internet address

ID: 32251596