Friday, May 17, 2013

Galileo's Unintentional Sunspot Animation

In the late spring and early summer of 1613, Galileo Galilei conducted a series of observations of the Sun. At the time, the study of sunspots was still obviously very young. Prior to the telescope, sunspots could be observed at sunrise or sunset (usually the latter), due to the strong filtering effects of the atmosphere at low angles. As the 17th century rolled along, the telescopic projection method of observing became the standard. It was Galileo's protege Benedetto Castelli who developed the method he used. From the 2nd of June through the 8th of July, 1612, Galileo made daily drawings from these observations, though a couple of days were missed (4th and 30th June). If you take the longest set, the 5th through the 29th of June, and arranged them in order, you get a crude animation showing the rotation of the Sun.

(I am not one to take credit where it isn't due. I would like to thank the Galileo Project at Rice University for the initial spark, primarily this page. I would also like to thank Professor Owen Gingerich of Harvard for providing valuable critiques of the work.)

No comments: