Shepherd's dial
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A shepherd's dial (also known as a pillar dial or cylinder) is a type of sundial that measures the of the sun via the so-called .[1] Its design needs to incorporate a fixed latitude, but it is small and portable. It is named after Pyrenean shepherds, who would trace such a sundial on their staffs. This type of sundial was very popular in the 16th, 17th and 18th centuries.
History[]
Since the ancient Roman era, people have created sundials which tell the time by measuring differences in the sun's height above the horizon over the course of the day – Vitruvius describes them as viatoria pensilia.[2] The earliest description of a shepherd's dial as known today was written by Hermann of Reichenau, an 11th-century Benedictine monk who called it a cylindrus horarius. It was also known in the Middle Ages as a chilinder oxoniensis (Oxford cylinder). Such sundials did not need aligning north-south and so became very popular,[3] appearing in Renaissance artworks such as Holbein's 1528 Portrait of Nicolaus Kratzer and his 1533 The Ambassadors.[4]
Concept[]
Characteristics[]
Variants[]
A Slovenian shepherd's dial is a flat dial in the shape of a sector of a circle. It is hung vertically and measures the altitude of the sun. A movable peg adjusts for the changing seasons.[5]
References[]
- ^ Claudia Kren, (1977), The Traveler's Dial in the Late Middle Ages: The Chilinder, Society for the History of Technology, Vol. 18, No. 3 (Jul., 1977), pp. 419–435
- ^ Derek De Solla Price, (1969), "Portable sundials in the antiquity", Centaurus, 14, págs. 242–266
- ^ Allan A. Mills, (1996), Altitude sundials for seasonal and equal hours, Annals of Science, Vol. 53, nº 1, doi: 10.1080/00033799600200121, pags. 75–85
- ^ Stebbins, F. A., (1962), The Astronomical Instruments in Holbein's "Ambassadors", Journal of the Royal Astronomical Society of Canada, Vol. 56, pág.45
- ^ http://thezaurus.org/webzine/indexb97b.html?/webzine/shepherds_sundial
- Sundials