A History of Sundials

Introduction

The concept of time isn't just two needles in a circle (or sometimes an oval, or a square, or a rectangle - you get the point! ), but it's more than that. Time is the immortal duration of events that happens in the world, and, we have found a way to understand the value of time and read it.

But, time wasn’t always the way we know it today. Humans earlier clearly didn’t have the privileges like clocks, smartphones, smart watches, analogue watches, and god knows how many more! They had to rely on their shadowy friends, the sundials.

Sundials in Ancient Egypt:

The Ancient Egyptians were the first to discover time. They made devices in which you could read the time from the shadow and the sun's position. They also might have used these to tell the horoscope, sign, and other astrological purposes, like to say the fate of royalties on birth. Just imagine checking your horoscope and seeing: "Today, you will encounter a tall, dark stranger. Well, it's either a cloud or your neighbour, hard to say."

Earliest Egyptian Sundial: 

The first sundial was flat and semi-circled. It had a pointer, called the “gnomon”, on the top centre and 12 equidistant lines extending from the centre. These sundials were positioned depending on the location of the sun. When the sunlight fell on the gnomon, the shadow would cast on the numberings, telling the time roughly. These were later updated to be slightly curved.

The flat limestone sundials consisted of a rectangular slab of stone with markings and hour lines carved into its surface. The slab was positioned horizontally, and a vertical gnomon or style was placed in the centre. The gnomon casts a shadow on the slab, allowing for the measurement of time. These early sundials were relatively simple in design and construction compared to the later obelisk sundials. They were portable and often made from small limestone blocks. The hour lines and markings on the surface were used to indicate the divisions of the day, allowing for the estimation of time-based on the position of the shadow.

The angle of the gnomon is set to align with the latitude of the location where the sundial is installed. As the sun moves across the sky throughout the day, the shadow cast by the gnomon falls on the marked hour lines, indicating the time.

The Egyptian L Shaped Sundial

The L-shaped sundial is a type of sundial design characterized by its distinctive shape resembling the letter "L." It is also referred to as a vertical sundial due to its vertical orientation. The L-shaped sundial consists of a vertical plane, usually made of stone or metal, with hour lines and numbers marked on its surface.

The L-shaped sundial offers advantages over other designs in terms of accuracy and precision. By adjusting the angle of the gnomon to match the latitude, it can accurately track the movement of the sun and provide more precise time readings. This type of sundial became popular during the Renaissance and has been used in various architectural structures, gardens, and public spaces. It continues to serve as both a functional timekeeping device and an aesthetic element in outdoor settings.

The Egyptian Obelisk Sundials

Courtesy: National Institute of Standards and Technology

The obelisk sundials, featuring a vertical obelisk-shaped gnomon, came into use later in ancient Egypt. Obelisks were towering stone pillars with pointed tops that were originally constructed as monumental structures and symbols of power and were later adapted for use as sundials. I guess the Egyptians wanted to make sure their sundials were as monumental as their pyramids!

The obelisk sundials utilized the shadow cast by the gnomon on the surrounding ground to determine the time. The angle and position of the gnomon's shadow provided a more accurate indication of the time compared to the flat limestone sundials

The Egyptian Cylindedral Sundial

Cylindrical sundials consisted of a cylindrical or conical shape with a central hole or rod that acted as the gnomon. The gnomon was positioned vertically in the centre of the cylinder, allowing it to cast a shadow on the interior of the surface.

The interior was marked with hour lines and other divisions to indicate the time. These markings were often evenly spaced and radiated outwards from the central axis. The position of the shadow cast by the gnomon on these hour lines allowed the observer to determine the time of day.

You may want to note that cylindrical sundials were not exclusive to ancient Egypt and were used in other cultures as well. However; they were indeed present in Egyptian civilization, and examples have been found in archaeological excavations.

Sundials in Ancient Mesopotamia (Babylon)

The Babylonian Equatorial Sundial:

The Equatorial Sundial was a sophisticated device that played a crucial role in marking the significant events in the astronomical calendar. It consisted of an inclined plane with a gnomon positioned perpendicular to it. This alignment allowed the Babylonians to precisely track the movement of the sun along the celestial equator. By observing the shadow cast on the inclined plane, they could determine the precise moment of the equinoxes, which held great importance for agricultural planning and celestial observations. Equatorial Sundial showcased Babylonians' ability to integrate timekeeping with their agricultural practices and astronomical pursuits.

The Babylonian Boustrophedon Sundial:

The Babylonian boustrophedon sundial is an ancient timekeeping device used by the Babylonians in the 6th century BCE. "Boustrophedon" refers to a style of writing or carving in which the text is inscribed in alternating directions, like the ploughing pattern of an ox (from which the term is derived). The sundial gets its name because the shadow moves in a boustrophedon pattern, changing direction periodically. The Boustrophedon Sundial was a remarkable example of the Babylonians' creativity in timekeeping. Its unique pattern of hour lines allowed time to be read in two directions, providing flexibility and convenience. As the sun's shadow moved along the sundial, observers could read the time by following the hour lines in alternating directions. This innovative design catered to different viewing angles and provided a practical solution for measuring time accurately, regardless of the sun's position. The Boustrophedon Sundial exemplified the Babylonians' ability to think outside the box and develop inventive solutions to everyday challenges.

The Babylonian Pillar Sundial:

The Pillar Sundial was a grand and monumental timekeeping device that adorned public spaces, temples, and royal complexes. These sundials featured tall vertical pillars with distinct markings. The shadow cast by the pillars fell on the hour lines, enabling the Babylonians to read the time accurately. The Pillar Sundials showcased the Babylonians' architectural and engineering prowess, as these imposing structures served as timekeepers and symbols of their civilization's technological advancements. These grand sundials stand as a testament to the Babylonians' ability to blend aesthetics, functionality, and precision into their timekeeping devices.

Sundials in Ancient China

The Chinese Quadrant Sundials:

Quadrant sundials were commonly used in ancient China and were based on the principle of a quarter-circle. These sundials had a quadrant-shaped plate with hour lines and divisions, allowing for accurate time measurement. The gnomon was placed at the centre of the quadrant, and the shadow it cast indicated the time based on the position of the sun. Quadrant sundials were often made of bronze or other metals and were highly valued for their precision.

The Chinese Hemispherical Sundials:

Hemispherical sundials were another type of sundial used in ancient China. These sundials had a spherical shape, with hour lines and markings engraved on the inner surface. The gnomon, usually in the form of a vertical rod, was placed at the centre of the sphere. As the sun moved across the sky, the shadow cast by the gnomon on the inner surface allowed observers to determine the time. Hemispherical sundials were prized for their aesthetic appeal and scientific functionality.

The Chinese Tower Sundials:

Tower sundials were large-scale structures commonly found in ancient Chinese architecture. These sundials were integrated into the design of towers, pagodas, and other tall structures. The shadow cast by the tower or its elements served as a time indicator. Tower sundials showcased ancient China's ingenuity in blending timekeeping with architectural marvels, allowing for public timekeeping and astronomical observations.

Ancient China had a rich tradition of using sundials as both practical timekeeping devices and instruments for observing celestial phenomena. These sundials not only helped the Chinese track time accurately but also contributed to their understanding of astronomy, seasons, and the movement of celestial 

bodies. The intricate designs and precise craftsmanship of Chinese sundials reflect ancient Chinese civilisation's profound scientific and artistic achievements.

Sundials in Ancient Greece

The Greek Hemispherical Sundials:

Hemispherical sundials, also known as hemispherium, were among the earliest forms of sundials used in ancient Greece. These sundials feature a concave hemisphere with engraved hour lines and divisions.

World History Encyclopedia

The gnomon, usually in the form of a rod or pointer, was placed at the centre of the hemisphere. As the sun's rays struck the hemisphere, the shadow cast by the gnomon indicated the time. Hemispherical sundials were often made of stone or metal and were valued for their portability and ease of use.

The Greek Diptych Sundials:

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Diptych sundials are portable and versatile devices consisting of two flat panels hinged together. These sundials were commonly made of wood, ivory, or metal and featured engraved hour lines, markings, and a folding gnomon. Diptych sundials allowed users to adjust the angle of the panels and align the gnomon with the sun, providing accurate time measurement. They were compact and practical, making them popular among travellers, merchants, and scholars.

The Greek Cone Sundials:

Cone sundials, also known as conical sundials, were cylindrical or conical-shaped devices with hour lines and divisions engraved on their surface. The gnomon, positioned vertically at the apex of the cone, cast a shadow that moved along the hour lines as the sun travelled across the sky. Cone sundials were often made of stone or metal and were valued for their accuracy and ability to provide time measurement even during cloudy or overcast days.

The Greek Vertical Sundials:

Vertical sundials, also known as analemmatic sundials, were distinctive in their design and functionality. These sundials consisted of a flat horizontal surface with hour lines and markings, while the gnomon was a vertical rod or pointer. Unlike other sundials that relied on the sun's rays, vertical sundials utilized the user's shadow to indicate the time. The user would stand on a specific marked spot and align their shadow with the corresponding hour line, allowing for accurate time measurement.

Ancient Greece's fascination with sundials went beyond mere timekeeping. Sundials were seen as symbols of the Greeks' pursuit of knowledge, understanding, and the harmony of the cosmos. They were often incorporated into public spaces, temples, and important buildings, demonstrating the Greeks' appreciation for both the practical and aesthetic aspects of sundials. The ingenuity and precision of ancient Greek sundials laid the foundation for future advancements in timekeeping.

 

Sundials in Rome

The Roman Horizontal Sundials:

The most common type of sundial used in ancient Rome was the horizontal sundial. These sundials consisted of a flat horizontal plate with engraved hour lines and markings. The gnomon, usually in the form of a triangular or rod-shaped pointer, was positioned perpendicular to the plate. As the sun cast its rays, the gnomon's shadow fell on the hour lines, allowing observers to read the time. Horizontal sundials were typically made of stone or metal and could be found in public squares, temples, and private residences.

The Roman Portable Sundials:

Portable sundials, known as pocket sundials or diptych sundials, were favoured by Romans who needed to keep track of time while travelling or away from fixed timekeeping devices. These sundials consisted of two hinged panels, often made of metal or ivory, which could be opened and closed like a book. The interior of the panels featured engraved hour lines, markings, and a gnomon. Portable sundials allow the user to adjust the angle of the panels and align the gnomon with the sun, providing accurate time measurement on the go. These were also exclusively used by Egyptian priests.

The Roman Vertical Sundials:

Vertical sundials, also known as wall sundials or vertical declining sundials, were commonly found on the walls of buildings and structures in ancient Rome. These sundials utilized the south-facing wall as a vertical surface on which hour lines and markings were engraved. The gnomon, positioned at a specific angle, cast a shadow that moved along the hour lines as the sun traversed the sky. Vertical sundials require precise alignment with the cardinal directions to ensure accurate time measurement.

The Roman Hemispherical Sundials:

Hemispherical sundials, similar to their Greek counterparts, were also used in ancient Rome. These sundials feature a concave hemisphere with engraved hour lines and divisions. The gnomon, typically in the form of a rod or pointer, was placed at the centre of the hemisphere. As the sun's rays struck the hemisphere, the shadow cast by the gnomon indicated the time. Hemispherical sundials were valued for their portability and ease of use, and they often adorned gardens and courtyards.

The Roman Cube Sundials:

Cube sundials, also known as cubic sundials or polyhedral sundials, were unique timekeeping devices that incorporated multiple faces to measure time accurately. These sundials had six or more faces, each with its own set of hour lines and markings. The faces of the cube were positioned at specific angles to align with the sun's movement throughout the day. Cube sundials provided precise time measurements and were particularly favoured by Roman engineers and astronomers.

Roman sundials were not merely functional timekeeping devices but also showcased the Romans' artistic sensibilities. Many sundials were adorned with intricate carvings, inscriptions, and decorative motifs, highlighting the Romans' love for aesthetics and beauty.

 

Sundials in The Islamic Civilization

(Islamic sundials were influenced by earlier civilizations such as the Egyptians, Greeks, and Romans. Muslim scholars and scientists studied and built upon the knowledge of these ancient cultures, adapting and refining their techniques to suit the needs of Islamic society.)

The Universal Sundial:

The most common type of sundial found in Islamic civilization was the universal sundial, also known as the equinoctial sundial. This type of sundial could be used anywhere in the world, making it particularly practical for Islamic scholars and travellers who journeyed across vast territories. The universal sundial featured an inclined plate with hour lines and a gnomon positioned parallel to the Earth's axis. By aligning the gnomon with the North Star or the sun's position, the user could accurately determine the time.

The Islamic Vertical and Horizontal Sundials:

Islamic sundials included both vertical and horizontal variants. Vertical sundials, often affixed to the sides of buildings or placed in prominent locations, used a gnomon to cast a shadow on a vertical surface marked with hour lines. Horizontal sundials, similar to those seen in other cultures, featured a flat surface with engraved hour lines and a gnomon perpendicular to the surface. These sundials were particularly prevalent in courtyards and public spaces.

The Islamic Mosque Sundials:

Sundials were commonly incorporated into mosque architecture in Islamic civilization. These mosque sundials served as essential tools for determining the time of daily prayers (salah) and were strategically positioned to accurately catch the sun's rays. Mosque sundials ranged from simple horizontal designs to more elaborate structures, often adorned with intricate geometric patterns and inscriptions from the Quran.

 

Sundials in Medieval Europe

Sundials in Medieval Europe were deeply influenced by the early Christian Church, which sought to establish a more unified and regulated system for prayer and religious observance. Sundials were used to determine the canonical hours, which marked specific times of the day for prayer. Monasteries and cathedrals often featured sundials as an integral part of their architectural design.

The European Horizontal Sundials:

The most common type of sundial in Medieval Europe was the horizontal sundial. These sundials consisted of a flat plate with engraved hour lines and a raised gnomon that cast a shadow on the surface. The hour lines were typically marked with Roman numerals, and the gnomon's position and shadow indicated the time. Horizontal sundials were placed in open areas, such as gardens or courtyards, where they could receive direct sunlight.

The European Vertical Sundials:

Vertical sundials were also prevalent in Medieval Europe, particularly in urban areas. These sundials were mounted on vertical surfaces, such as the sides of buildings or church facades. Vertical sundials featured an inclined plate with engraved hour lines and a gnomon that projected a shadow on the surface. They are often placed on south-facing walls to receive maximum sunlight throughout the day.

The European Portable Sundials:

In addition to fixed sundials, portable sundials became popular during the late Medieval period. These handheld devices allowed individuals to carry a personal timekeeping instrument wherever they went. Portable sundials are typically small and made of metal, such as brass or bronze. They often had folding designs to protect the delicate mechanisms and were engraved with hour lines and markings.

Astrolabes:

While not strictly a sundial, astrolabes were widely used in Medieval Europe for timekeeping, astronomical observations, and navigation. Astrolabes were intricate instruments that utilised the position of celestial bodies, including the sun, to determine the time and assist in various calculations. It featured rotating dials, engraved markings, and movable components that allowed users to align the instrument with celestial objects.

Conclusion:

Sundials not only served as practical timekeeping instruments but also symbolised the pursuit of knowledge, the harmony of the cosmos, and the ingenuity of human creativity. They were integrated into public spaces, temples, and architectural marvels, leaving behind a rich legacy of scientific and artistic achievements. From the simple yet effective designs of early sundials to the more intricate and precise constructions, each civilization left its mark on the evolution of these timekeeping devices. While sundials may have been replaced by more advanced timekeeping technologies in modern times, their historical significance and cultural value remain intact. They serve as reminders of our ancestors' curiosity, resourcefulness, and connection to the celestial world. Exploring the history and diversity of sundials allows us to appreciate the ingenuity and craftsmanship of ancient civilizations and gain a deeper understanding of our shared human heritage.
Despite the changing tides of technology, sundials remind us that the measurement of time is not just about numbers and precision but also about our innate connection to the celestial rhythms that shape our world.
So, the next time you see a sundial, take a moment to admire its elegance and contemplate the timeless wisdom it represents.