Observations by Christoph Scheiner
Christoph Scheiner (1575–1650) was a Jesuit priest, physicist, and astronomer. The Biblioteca Nazionale Centrale of Florence (BNCF) stores one redraw of his illustration. In Data, this single observation is added to the set of observations by Fabio Colonna.
1 Aug 1613
This illustration by Christoph Scheiner was redrawn by Welser (1613) in his letter to Galilei dated 18 October 1613. Welser quoted Scheiner (translated by Mitchell (1916)): "I add, therefore, an observation made on the first day of August, in which you will see examples of this ew sight. However, these are not sun-spots, but are "little torches" (faculae), that is, regions which are brighter than those surrounding them...". Faculae are mentioned to be marked with letters a, b, and c on the drawing ("..secus tres a,b,c, Sunt autem eæ non maculae Solis, sed faculae,.."). We separated faculae from sunspots when processing this drawing.
This drawing is schematic and its style is similar to that by Cigoli in February – March 1612 and Galilei in February – May 1612. The solar disk is almost a perfect circle with a diameter of a few centimeters. Scheiner's original observation was made by means of projecting with a tube on a card. The drawing is supplemented by a note "1. Aug. P.M. solis elevatio. 26 deg 0'.". Location is Ingolstadt (Arlt et al. 2016).
