The Basilica of the Duomo contains, inside, a beautiful sundial, unfortunately no longer functional due to artificial lighting. Near the entrance of the Duomo, in fact, there is a sundial with the symbol of Capricorn, consisting of a brass strip embedded in the floor that crosses the nave and goes up for three meters on the left wall to the north. On the south-facing wall, at a height of almost 24 metres from the floor, there is a hole through which, at solar noon, a ray of light is projected onto the strip of floor. In order to avoid that on some days of the year the hole through which the light enters ends up in shadow, the marble arch is missing on the south side of the church. On either side of the metal line are marble slabs indicating the signs of the zodiac with the dates of the sun’s entrance. The instrument was made in 1786 by the astronomers of Brera, restored several times and modified in 1827 following the reconstruction of the floor of the Cathedral.
