Santa Maria Novella
Detail #4

Santa Maria Novella as seen from the Piazza Santa Maria Novella. The lower part of the face was designed by Talenti around 1340 while the upper facade with its rose window was the work of Alberti and completed between 1453-1470. Egnatio Danti placed a quadrant and an armillary sphere on the lower facade. The support for the quadrant is visible on the far right of the face.

Danti was a solar astronomer. He placed a small hole in the edge of the rose window in the upper facade. Sunlight entered the hole and fell on the floor of the church. A meridian line was marked on the floor and the progress of the sun through the seasons could be studied by the movement of the light across the meridian line. There is a similar hole in the dome of Santa Maria del Fiore (Duomo).

Ref: Egnatio Danti's Great Astronomical Quadrant by Maria Luisa Righini Bonelli and Thomas B. Settle, Istituto e Museo di Storia della Scienza-Firenze.