June 1996 page 10
Girolamo Fantoni

Azimuth Sundials Horizontal and Vertical

An in-depth exploration of azimuth sundials, comparing projection methods, construction techniques, and their advantages, with historical and modern examples.
Dials: Horizontal, Dials: Vertical, How Sundials Work, Mathematics of Dialling

June 1994 page 7
Girolamo Fantoni

Celestial Dials: An Unusual 'Nocturnal'

This article explores early timekeeping devices designed for night use, especially nocturnals, which rely on the stars. The main focus is on an unusual 18th-century portable nocturnal made in Granada by Cecyl Yode, with reversed hour scales likely referencing Sirius and Vega. The piece blends astronomy, craftsmanship, and mystery.
Dials: Portable, Historical Dials

October 1994 page 29
Girolamo Fantoni

The Gregorian Reformation of the Calendar

This article explains the historical context and mechanisms of the Gregorian calendar reform, initiated by Pope Gregory XIII in 1582 to correct discrepancies in the Julian calendar, particularly concerning the accurate determination of Easter. It traces the problem back to the Council of Nicea in AD 325 and the slight error in the solar year's length as calculated by Sosigenes. The reform involved dropping ten days and introducing a new leap year rule. The article also discusses the varying adoption rates across European countries, initial doubts within the Vatican (leading to the construction of a meridian line to verify accuracy), and briefly touches upon modern discussions regarding calendar improvements.
Equation of Time

October 1994 page 32
Girolamo Fantoni

Windows and Balconies as Simple Sundials

This article explores the concept of using shadows cast by window sills, jambs, and parapets on floors and walls as simple sundials. It explains the gnomonic principles involved, detailing how the moving "shadow straight line" can indicate the hour. The author provides formulas and diagrams for calculating the shadow's position based on latitude, window sill height and orientation (declination), solar altitude, and azimuth. It outlines the process of drawing date and hour lines, noting practical considerations like difficult-to-read periods for certain sill orientations, and suggests applications for terraces and balconies, or even for single hour lines with time-zone and Equation of Time corrections.
DIY Sundial Projects, Dials: Unusual, Mathematics of Dialling, Sundial Design & Layout

June 1992 page 10
Girolamo Fantoni

The Monumental Sundial in the Quirinale Gardens in Rome

This article describes a unique monumental cubical-cylindrical sundial from 1628 in Rome's Quirinale Gardens, 2.70 meters high, constructed of white marble. It features four concave quadrants indicating both civil/astronomical time and 'Italian time,' reflecting different timekeeping systems. The dial also includes zodiacal curves for calendrical indications and intricate Latin inscriptions from its author Theodosius Rubeus and patron Urbano VIII Barberini.
Dials: Cube, Dials: Multi Faced, Dials: Unusual, Historical Dials