-Galileo's Sunspots

Difficult to observe until the advent of the telescope, Galileo was among the first people to systematically document sunspots in 1610. In this work, he provides illustrations depicting the location, size, and shape of sunspots that he had observed by projecting the sun onto paper through a telescope. The presence of these spots challenged the Aristotelian model of perfect celestial spheres and provided evidence against the Ptolemaic geocentric model of the universe. By comparing these observations over time, it is possible to document the movement of sunspots across the sun. The nature of sunspot analysis would remain unchanged for nearly 300 years.

Gift of Robert B. Honeyman, ‘20

Lehigh University Catalog Record: https://asa.lib.lehigh.edu/Record/258624

A version of this text has been digitized and is available through the Internet Archive.

Galileo Galilei (1564-1642).
Istoria e dimostrazioni intorno alle macchie solari e loro accidenti comprese in tre lettere.
Rome: Appresso Giacomo Mascardi, 1613.