Florence’s Duomo is a Sundial Every June

Photo from Claudio Giovannini. Duomo

Everyone hears about the sun peeking up over the horizon, through the clouds, through the rain. But has anyone ever heard of the sun peeking through a building? It’s possible to see that happen in the Duomo during the month of June.

This event is a unique, one-of-a-kind event on the summer solstice: the summer sun will peek through a circular window in the cupola of the Duomo to the floor. The windows built into the cupola will reflect onto a small bronze plate inside of the dome. above the left transept of the church.

This bronze plate reflects the sunlight along the wall as the sun moves. This bronze plates functions as the gnomone of a sundial, the metal piece that juts out of a sundial which casts a shadow on the time or date.

Located on the floor, there is a small white marble circle, seemingly innocuous, set into the floor. The circle is not nearly so out of place as it may seem: the sun on the summer solstice in this time frame will fit perfectly into the circle on the summer solstice on the second, while inching closer and closer on the days beforehand.

The de-facto sundial was designed and place by Florentine mathematician Paolo da Pozzo Toscanelli. Toscanelli was the first and foremost mathematician in Italy, born in 1397 and deceased in 1482. He remained in Florence for all his life and fostered a deep friendship with Brunelleschi, the architect of the cupola.

With his expertise in math and fascination with astronomy, Toscanelli was the perfect man in Brunelleschi’s opinion to build such an expansive cupola, complete with his own touches such as this device. While Toscanelli died before the completion of the dome, which was finished in 1500, his designs were still utilized.

From 12:30 pm to 1:30 pm on several occasions in June, the general public is invited to view the passage of the sun in the Duomo. On June 21, the accompanying explanation will be in Italian, while, on June 20, it is will take place in English.

Reservations are required for each day. Email eventi@operaduomo.firenze.it or call 055.2302885 to make a reservation. While it is free, there are a limited number of seats. (katy rose sparks)