In 1612 during the summer months, Galileo made a series of sunspot observations which were published in Istoria e Dimostrazioni Intorno Alle Macchie Solari e Loro Accidenti  (History and Demonstrations Concerning Sunspots and their Properties, published 1613). Because these observations were made at appoximately the same time of day, the motion of the spots across the Sun can easily be seen. To illustrate this, thirty-six of Galileo's sunspot drawings have been placed in sequence as a "stop-motion" animation.
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