Sundials have fascinated us for millennia, connecting the heavens to the earth. Although the oldest known example is an ancient Egyptian shadow clock dating from around 1500BC, it was the Romans who were probably the first to use sundials in gardens and are believed to have been erected to honour Sol, the Roman god of the Sun.
The invention of clocks is often blamed on the demise of sundials, although early clocks were inaccurate and needed to be regularly recalibrated by comparing to a sundial! Indeed, right up to the end of the 19th century, French railways were still using sundials. However, in the 21st century, sundials are normally considered objects of beauty and cannot compare to the accuracy of the electronic masterpieces most of us wear on our wrists.
Most sundials today take the form of either a Wall Sundial, an Armillary Sphere Sundial or a flat plate sundial. ORNAMENTI offers the following:
Apollo Wall Sundial in hand-carved Vicenza limestone
Armillary Sphere Crescent Sundial in solid brass
Armillary Sphere sundials typically feature interlocking rings depicting the equator, meridian and colure, together with a gnomon. The metal rings are referred to as armilla, Latin for bracelet. An armillary sphere is ideally suited as a sundial. With hours inscribed on the inner surface of the Equator ring, the shadow of the gnomon onto the Equator ring is what gives you the time. As the sun moves across the sky during the course of a day, the gnomon’s shadows change as well, thus reflecting the change in time.
For every degree that the Earth rotates, the sun appears to move one degree across the sky. As it takes the sun 4 minutes to cover 1 degree, and an hour to cover 15 degrees, a full 360 degree rotation takes 24 hours. Quite simply, if you know where South is, you can tell the time. If the sun is due South at midday, and due North (unseen) at midnight, then at 6am the sun will be due East, and at 6pm the sun will be at due West. Sundials simply follow this logic.
Sundials do not tell Mean Time (clock time) but Local Apparent Time. Although a well made sundial can be very accurate, sundial time is slightly different to clock time due to natural irregularities in the path of the shadow cast on a sundial. The difference between sundial time and clock time varies throughout the year, peaking at 16 minutes and averaging out at four minutes. This is explained by the complex “Equation of Time”. For a detailed explanation, we suggest looking at the British Sundial Society website.
The location of a sundial is important as they only work when in direct sun! A sundial needs to be located in full sunlight throughout the day in order to tell the time all day long. Partial sun is acceptable if you are content for your sundial to tell the time for only part of the day. However, if the aesthetics of the sundial are the main requirement, then a sundial can literally go anywhere – sun, shade, or somewhere in between. But do remember that Sundials do not understand daylight saving time: so in the summer you will need to add an hour onto the time shown to take account of British Summer Time.
Wall Sundials are more restricted as to where they can be positioned if they are to work as designed. A Wall Sundial needs to be positioned on a South facing wall.
Sundials provide a great way to connect with the past and a salutary reminder of the inexorable passage of time. Armillary Sphere Sundials and Wall Sundials bring a timeless beauty and elegance to any garden or landscape as they combine artistic and scientific qualities and can be enjoyed from a distance, unlike flat dials. They will also last a lifetime, making them a perfect gift for many occasions – weddings, birthdays, retirements and the like.