Painted lunar sundial
The stainless steel rod, positioned so as to be parallel to the earth’s rotation axis, allows the reading of the true local time by means of the shadow generated by the sun during the day and the reading of the true local time at night, through the light. solar reflection from the moon in the days close to the full moon.
For a greater graphic balance of the dial, the hours in the upper part of the dial have also been plotted in the lunar diagram, where it is practically impossible to cast the shadow of the stylus.
Brown astronomical hour lines, drawn only in their terminal part near the frame and numbered with Roman numerals. The passage of the shadow of the steel rod marks Cantello’s true solar time, to which, according to the observation date, the minutes of the central graph at the top can be added,
On clear nights, when the full moon is present, and in the 5-7 days before and after the full moon, our satellite, reflecting the sunlight, can generate shadows useful for reading the time.
The concentric lines painted in red represent the 14 nights at the turn of the full moon night and are the nights when the moon can generate enough light to allow the time to be read
The time is read by observing the moon’s shadow moving on the circle from the red line, corresponding to the night of the lunation in which the observation is made (AGE OF THE MOON IN DAYS indicated on the left of the diagram with red numbers).