Frescoed sundial above the entrance, on a facade facing west. On the dial was painted the layout of an astrolabe specially designed for the same location as the dial of the sundial. Both the hour diagram of the astrolabe and the hour diagram in the center of the sundial dial show our ancient Italian time system. The two diagrams allude to the whole being mirrored in the part and vice versa. The diagram of the astrolabe shows the whole, the entire celestial vault represented by the stereographic projection. While the sundial diagram shows only the part of the sky visible from that side of the house.

The shadow of the polar style, scrolling on the dial, indicates the true solar time of the place, traced on the frame with Roman numerals. The flow of the shadow of the golden sphere on the central part of the diagram indicates the solstices, the equinoxes and the Italic hours numbered with remaining hours, to indicate more easily the hours of light that are missing at sunset.