Digital Survey of the Celestial Dome in the Old Sacristy of San Lorenzo in Florence

Abstract The article discusses the analysis of the measurements of the starry sky painted on the dome of the Old Sacristy of San Lorenzo (Florence). The investigation delves into the theme of the astronomical dating of the work and the attribution of the project. Using technologies such as laser scanning and digital photogrammetry, a detailed 3D model of the dome was created, allowing for the measurement of the positions of the celestial circles and the depicted stars. The study presents an increase of the number of measurements related to the celestial bodies painted on the dome (previously measured by scholars). It proposes a comparison between the obtained data and the astronomical sources available in the first half of the 15th century, in particular Ptolemy’s Almagest and the charts of Paolo dal Pozzo Toscanelli, in order to deepen the understanding of this unique representation and the astronomical skills involved in its creation.