In 1611, Scheiner observed sunspots; in 1612 he published the "Apelles letters" in Augsburg.
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One of Scheiner’s letters to Leopold from 1626 informs the Archduke that Galilei is not to hear of Scheiner’s work concerning the sunspots.
Noting that the rings were thinner in dry years, he reported climate effects from solar variations, particularly in connection with the 17th-century dearth of sunspots (the Maunder Minimum) noticed previously by William Herschel and others.