History of sundials

A sundial is a device that indicates time by using a light spot or shadow cast by the position of the Sun on a reference scale.[4] As the Earth turns on its polar axis, the sun appears to cross the sky from east to west, rising at sun-rise from beneath the horizon to a zenith at mid-day and falling again behind the horizon at sunset. Both the azimuth (direction) and the altitude (height) can be used to create time measuring devices. Sundials have been invented independently in every major culture and become more accurate and sophisticated as the culture developed. [5]

Ancient-egyptian-sundial
World's oldest known sundial, from Egypt's Valley of the Kings (c. 1500 BC), used to measure work hours.[1][2][3]

Introduction

A sundial uses local solar time. Before the coming of the railways in the 1830s and 1840s, local time was displayed on a sundial and was used by the government and commerce. Before the invention of the clock the sundial was the only source of time, after the invention, the sundial became more important as the clock needed to be reset regularly from a sundial- as its accuracy was poor. A clock and a dial were used together to measure longitude. Dials were laid out using straight edges and compasses. In the late nineteenth century sundials became objects of academic interest. The use of logarithms allowed algebraic methods of laying out dials to be employed and studied. No longer utilitarian, sundials remained as popular ornaments, and several popular books promoted that interest- and gave constructional details. Affordable scientific calculators made the algebraic methods as accessible as the geometric constructions- and the use of computers made dial plate design trivial. The heritage of sundials was recognised and sundial societies were set up worldwide, and certain legislations made studying sundials part of their national school curriculums. [5]

History

Ancient sundials

SunDialAiKhanoum
Hemispherical Greek sundial from Ai Khanoum, Afghanistan, 3rd–2nd century BCE
Stone sundial with Liubo markings
Chinese sundial of the Eastern Han dynasty, 2nd century AD
Sun dial stone, Kilmalkedar
Sundial stone, Kilmalkedar, Ireland (c. 7th century AD)

The earliest household clocks known, from the archaeological finds, are the shadow clocks (1500 BCE) in ancient Babylonian astronomy. Ancient analemmatic sundials of the same era (about 1500 BCE) and their prototype have been discovered on the territory of modern Russia.[6][7][8][9] Much earlier obelisks, once thought to have been used also as sundials, placed at temples built in honor of a pharaoh, are now thought to serve only as a memorial.[10] Presumably, humans were telling time from shadow-lengths at an even earlier date, but this is hard to verify. In roughly 700 BCE, the Old Testament describes a sundial — the "dial of Ahaz" mentioned in Isaiah 38:8 and 2 Kings 20:9 (possibly the earliest account of a sundial that is anywhere to be found in history) — which was likely of Egyptian or Babylonian design. Sundials are believed to have existed in China since ancient times, but very little is known of their history.[11] There is an early reference to sundials from 104 BCE in an assembly of calendar experts.[12]

The ancient Greeks developed many of the principles and forms of the sundial. Sundials are believed to have been introduced into Greece by Anaximander of Miletus, c. 560 BCE. According to Herodotus, Greek sundials were initially derived from their Babylonian counterparts. The Greeks were well-positioned to develop the science of sundials, having founded the science of geometry, and in particular discovering the conic sections that are traced by a sundial nodus. The mathematician and astronomer Theodosius of Bithynia (ca. 160 BCE-ca. 100 BCE ) is said to have invented a universal sundial that could be used anywhere on Earth.

The Romans adopted the Greek sundials, and the first record of a sundial in Rome is 293 BC according to Pliny.[13] Plautus complained in one of his plays about his day being "chopped into pieces" by the ubiquitous sundials. Writing in ca. 25 BC, the Roman author Vitruvius listed all the known types of dials in Book IX of his De Architectura, together with their Greek inventors.[14] All of these are believed to be nodus-type sundials, differing mainly in the surface that receives the shadow of the nodus.

The Romans built a very large sundial in 10 BC, the Solarium Augusti, which is a classic nodus-based obelisk casting a shadow on a planar pelekinon.[15] The Globe of Matelica is felt to have been part of an Ancient Roman sundial from the first or second century.

The custom of measuring time by one's shadow has persisted since ancient times. In Aristophanes' play, Assembly of Women, Praxagora asks her husband to return when his shadow reaches 10 feet (3.0 m). The Venerable Bede is reported to have instructed his followers in the art of telling time by interpreting their shadow lengths. However, Bede's important association with sundials is that he encouraged the use of canonical sundials to fix the times of prayers.

Renaissance sundials

The onset of the Renaissance saw an explosion of new designs. Italian astronomer Giovanni Padovani published a treatise on the sundial in 1570, in which he included instructions for the manufacture and laying out of mural (vertical) and horizontal sundials. Giuseppe Biancani's Constructio instrumenti ad horologia solaria (ca. 1620) discusses how to make a perfect sundial, with accompanying illustrations.

The dials of Giovanni Francesco Zarbula

Painted vertical declining dials in villages around Briançon, Hautes-Alpes, France. There are 400 painted dials in this one French department dating form the 18th and 19th centuries. The most famous sundial maker was Giovanni Francesco Zarbula (fr) who created a hundred of them between 1833 and 1881.

Modern dialing

The Greek dials were inherited and developed further by the Islamic Caliphate cultures and the post-Renaissance Europeans. Since the Greek dials were nodus-based with straight hour-lines, they indicated unequal hours — also called temporary hours — that varied with the seasons, since every day was divided into twelve equal segments; thus, hours were shorter in winter and longer in summer. The idea of using hours of equal time length throughout the year was the innovation of Abu'l-Hasan Ibn al-Shatir in 1371, based on earlier developments in trigonometry by Muhammad ibn Jābir al-Harrānī al-Battānī (Albategni). Ibn al-Shatir was aware that "using a gnomon that is parallel to the Earth's axis will produce sundials whose hour lines indicate equal hours on any day of the year." His sundial is the oldest polar-axis sundial still in existence, and a replica can still be seen on Madhanat ul-'Urus, one of the minarets of Umayyad Mosque[16]. The concept later appeared in Western sundials from at least 1446.[17][5]

The oldest sundial in England is a tide dial incorporated into the Bewcastle Cross, Cumbria, and dates from the 7th or early 8th century.

Twentieth and twenty-first century dialing

Designers of the Taipei 101, the first record-setting skyscraper of the 21st century, brought the ancient tradition forward. The tower, tallest in the world when it opened in Taiwan in 2004, stands over half a kilometer in height. The design of an adjoining park uses the tower as the style for a huge horizontal sundial.

Gallery

Cadran solaire Kairouan

Old sundial located in the Great Mosque of Kairouan also known as the Mosque of Uqba, in Kairouan, Tunisia.

Sundial on Gravestone at Kilbirnie

A Scottish gravestone bearing a sundial. The instrument has often doubled as a memento mori.

Bibury St. Mary - Mass Dial - geograph.org.uk - 365475

A medieval mass dial (minus its gnomon) at St. Mary, Bibury; also known as a scratch dial, it was used to tell the times of Mass.

Death Sundial

This sundial displays a likeness of Father Time. Its motto quotes Robert Browning: "Grow old along with me; the best is yet to be."

Klagenfurt Europapark sundial 11102008 01

Marble equatorial sundial in the Europapark of Klagenfurt on Lake Woerth, Carinthia, Austria

Jantar Mantar in Jaipur giant sundial

The Giant Sundial of Jantar Mantar in Jaipur, India, stands 27m tall. Its shadow moves visibly at 1 mm per second. 26°55′29″N 75°49′29″E / 26.9247°N 75.8248°E

Göttingen Cubic Sundial cropped smaller

Several sundials arrayed on the faces of a cube. The styles are all parallel and meant to be aligned with the Earth's rotation axis.

Modern
Präzissions-Sonnenuhr

Martin Bernhardt created a special gnomon for an equatorial sundial which adjusts for the equation of time and that allows one to read the time without knowing the date, to a precision of less than a minute.

Seoul-Gyeongbokgung-Sundial-02

A modern hemispherium in Gyeongbok Palace in Seoul, South Korea. 37°34′43″N 126°58′38″E / 37.578611°N 126.977222°E The pointer tip acts as the nodus; the height of the nodus-shadow gives the time of the year.

Precision sundial in Bütgenbach-Belgium

High precision (±30 seconds) sundial in Belgium (Google Earth)

See also

References

Notes
  1. ^ Preliminary Report on the Work carried out during the season 2013
  2. ^ Bickel, S.; Gautschy, R. Eine ramessidische Sonnenuhr im Tal der Könige. Zeitschrift für Ägyptische Sprache und Altertumskunde 2014, Volume 96, Issue 1, pp. 3-14.
  3. ^ Vodolazhskaya, L.N. Reconstruction of ancient Egyptian sundials. Archaeoastronomy and Ancient Technologies 2014, 2(2), 1-18.
  4. ^ Jones 2005, p. 1.
  5. ^ a b c Jones 2005.
  6. ^ Vodolazhskaya, L.N.; Larenok, P.A.; Nevsky, M.Yu. Ancient astronomical instrument from Srubna burial of kurgan field Tavriya-1 (Northern Black Sea Coast). Archaeoastronomy and Ancient Technologies 2014, 2(2), 31-53.
  7. ^ Vodolazhskaya, L.N. Analemmatic and horizontal sundials of the Bronze Age (Northern Black Sea Coast). Archaeoastronomy and Ancient Technologies 2013, 1(1), 68-88.
  8. ^ Vodolazhskaya L.N., Larenok P.A., Nevsky M.Yu. The prototype of ancient analemmatic sundials (Rostov Oblast, Russia). Archaeoastronomy and Ancient Technologies 2016, 4(1), 96-116.
  9. ^ Vodolazhskaya, L.N.; Larenok, P.A.; Nevsky, M.Yu. Solnechnye chasy epokhi bronzy iz srubnogo pogrebeniya mogil'nika Tavriya-1. [Sundial of Bronze Age from the Srubna burial of kurgan field Tavriya-1]. Istoriko-arkheologicheskiy al'manakh. [Historical-Archaeological Almanac]. Vol. 13, Armavir, Krasnodar, Moscow, 2015, p. 4-14.
  10. ^ The oldest surviving sundial
  11. ^ "Sundials in China - A brief note". The University of Hong Kong. 1997-07-01. Archived from the original on 2010-03-14. Retrieved 2010-01-20.
  12. ^ Joseph Needham (1959). Science and Civilisation in China. 3. C.U.P. p. 302.
  13. ^ Pliny (79ce): Natural History 7.213
  14. ^ "Marcus Vitruvius Pollio:de Architectura, Book IX". The Latin text is that of the Teubner edition of 1899 by Valentin Rose, transcribed by Bill Thayer. 2007-07-07. Retrieved 2007-09-07.
  15. ^ Edmund Buchner, "Solarium Augusti und Ara Pacis", Römische Mitteilungen 83 (1976:319-75); Die Sonnenuhr des Augustus: Kaiser Augustus und die verlorene Republik (Berlin) 1988.
  16. ^ "ibn Shatir's Sundial at Umayyad Mosque". Madain Project. Retrieved 12 May 2019.
  17. ^ "History of the sundial". National Maritime Museum. Archived from the original on 2007-10-10. Retrieved 2008-07-02.
Bibliography
  • Jones, Lawrence (December 2005). "The Sundial And Geometry". North American Sundial Society. 12 (4).
  • Earle AM (1971). Sundials and Roses of Yesterday. Rutland, VT: Charles E. Tuttle. ISBN 0-8048-0968-2. LCCN 74142763. Reprint of the 1902 book published by Macmillan (New York).
  • A.P.Herbert, Sundials Old and New, Methuen & Co. Ltd, 1967.
  • Mayall RN, Mayall MW (1994). Sundials: Their Construction and Use (3rd ed.). Cambridge, MA: Sky Publishing. ISBN 0-933346-71-9.
  • Hugo Michnik, Theorie einer Bifilar-Sonnenuhr, Astronomishe Nachrichten, 217(5190), p. 81-90, 1923
  • Rohr RRJ (1996). Sundials: History, Theory, and Practice (translated by G. Godin ed.). New York: Dover. ISBN 0-486-29139-1. Slightly amended reprint of the 1970 translation published by University of Toronto Press (Toronto). The original was published in 1965 under the title Les Cadrans solaires by Gauthier-Villars (Montrouge, France).
  • Frederick W. Sawyer, Bifilar gnomonics, JBAA (Journal of the British Astronomical association), 88(4):334–351, 1978
  • Gerard L'E. Turner, Antique Scientific Instruments, Blandford Press Ltd. 1980 ISBN 0-7137-1068-3
  • J.L. Heilbron, The sun in the church: cathedrals as solar observatories, Harvard University Press, 2001 ISBN 978-0-674-00536-5.
  • Make A Sundial, (The Education Group British Sundial Society) Editors Jane Walker and David Brown, British Sundial Society 1991 ISBN 0-9518404-0-1
  • Waugh AE (1973). Sundials: Their Theory and Construction. New York: Dover Publications. ISBN 0-486-22947-5.
  • "Illustrating Shadows", Simon Wheaton-Smith, ISBN 0-9765286-8-1, LCN: 2005900674

External links

Diodorus of Alexandria

Diodorus of Alexandria or Diodorus Alexandrinus was a gnomonicist, astronomer and a pupil of Posidonius.

Hourglass

An hourglass (or sandglass, sand timer, sand clock or egg timer) is a device used to measure the passage of time. It comprises two glass bulbs connected vertically by a narrow neck that allows a regulated trickle of material (historically sand) from the upper bulb to the lower one. Factors affecting the time it measured include sand quantity, sand coarseness, bulb size, and neck width. Hourglasses may be reused indefinitely by inverting the bulbs once the upper bulb is empty. Depictions of hourglasses in art survive in large numbers from antiquity to the present day, as a symbol for the passage of time. These were especially common sculpted as epitaphs on tombstones or other monuments, also in the form of the winged hourglass, a literal depiction of the well-known Latin epitaph tempus fugit ("time flies").

Sundial (disambiguation)

Sundial or sun dial may refer to:

Sundial, a timekeeping device

Analemmatic sundial, showing more than just the time of day

Digital sundial, with digital display

History of sundials

Scottish sundial, decorative sundials of the renaissance period

Kirkdale sundial, Saxon sundial

Whitehurst & Son sundial (1812), very accurate sundial

Carefree sundial, very large sundial in Arizona

Sundial, Boy with Spider, Indianapolis Museum of Art

Sundial Bridge at Turtle Bay, bridge in Redding, California

List of sundial mottos

Term (time)

A term is a period of duration, time or occurrence, in relation to an event. To differentiate an interval or duration, common phrases are used to distinguish the observance of length are near-term or short-term, medium-term or mid-term and long-term.

It is also used as part of a calendar year, especially one of the three parts of an academic term and working year in the United Kingdom: Michaelmas term, Hilary term / Lent term or Trinity term / Easter term, the equivalent to the American semester. In America there is a midterm election held in the middle of the four-year presidential term, there are also academic midterm exams.

In economics, it is the period required for economic agents to reallocate resources, and generally reestablish equilibrium. The actual length of this period, usually numbered in years or decades, varies widely depending on circumstantial context. During the long term, all factors are variable.

In finance or financial operations of borrowing and investing, what is considered long-term is usually above 3 years, with medium-term usually between 1 and 3 years and short-term usually under 1 year. It is also used in some countries to indicate a fixed term investment such as a term deposit.

In law, the term of a contract is the duration for which it is to remain in effect (not to be confused with the meaning of "term" that denotes any provision of a contract). A fixed-term contract is one concluded for a pre-defined time, although it may also include provision for it to be extended. A contractor required to deliver against a term contract is often referred to as a "term contractor".

Zag de Sujurmenza

Rabbi Sujurmenza Zag was a Jewish convert of 13th-century Spain who helped King Alfonso X of Castile with his scientific works.

Zag de Sujurmenza was commissioned by the king to write Astrolabio redondo (spherical astrolabe), Astrolabio llano (flat astrolabe), Constelaciones (constellations) and Lámina Universal (an instrument that improved on the astrolabe); he also translated the book Armellas de Ptolemy, and wrote about the Piedra de la sombra (stone of the shadow, or sundial), Relox de agua (clepsydra, or water clock) Argente vivo o azogue (quicksilver or mercury) and Candela (candle clock). Of his works, the most important are those of the "round astrolabe" and the "flat astrolabe". In the first, the author rises to profound scientific considerations that reveal the vast knowledge he possessed in sciences. It has been said that with this book, Zag Sujurmenza reformed the character of the science of astronomy and contributed to its advancement, without losing sight of the studies of Arab scholars, following in their footsteps and correcting their errors. Other works of Zag de Sujurmenza, if less extensive, are not without merit.

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