The sundial

When I come home from the first international Olympiad I participated in 2015, I got the idea of building a sundial at my house. The idea remained vague due to lack of time and gnomonic knowledge until the summer 2020, when during the summer break I dedicated myself to the project and the realization of the solar clock I had imagined.

The dial is facing SW (233 ° 30 '), its dimensions are 260 x 263 cm and it has a slight inclination (20' upwards) due to the way the wall was built. Although the inclination is small, the size of the dial ensures that if this factor hadn't been considered, the bottommost points of the sundial would have been shifted almost 10cm.

The orthostyle is 29cm long and the polar style consists of two pointed bars about 30cm long fixed to the tip of the orthostyle.

The sundial marks the real time of the time zone +1. At the top, the Roman numbers tell the standard time, while at the bottom the arabic numbers tell the summer time. There are the lines for the hours, for the half-hours and the marks for the quarters of an hour. The equinox line is visible in blue.

Along the line of twelve o'clock, an analemma has been drawn to tell the civil time and the day of the year. The black signs along the analemma indicate the first day of each month (the number near the mark correspond to the month). Clearer notches were made to mark the date every five days.

The motto “... ed è subito sera” is the last line of namesake poem of Quasimodo and refers to the fact that the sundial works only in the afternoon and evening hours. The compass indicates the true North, while on the right reported the information about the dial are reported, in order: latitude, longitude, declination and inclination of the wall.

The compass drawn on the dial is properly aligned with the cardinal points if you, standing in font of the dial, imagine laying the drawing on a horizontal plane. The compass is made with acrylic and shaded with colored pencils, everything was properly fixed with transparent spray and fixative.

Below you can find a gallery of the construction phases of the sundial. At the bottom you can find the time-lapse of the sundial shadow on September 1, 2020 when the equation of time was 0, but the sundial not yet finished.