Macchie Solari

http://library.lehigh.edu/omeka/files/original/afc876790b202487b10d03083fbd82d0.jpg

Title page.

Istoria e dimostrazioni intorno alle macchie solari e loro accidenti comprese in tre lettere scritte all'illvstrissimo signor Marco Velseri ... Rome, Appresso Giacomo Mascardi, MDCXIII (1613).

In the summer of 1612, Galileo made a series of sunspot observations that were published in 1613.

http://library.lehigh.edu/omeka/files/original/2d02a93e8cc7c01e5250ed63fe58da69.jpg

Sunspot diagrams.