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Germany, Baden-Württemberg, D-73207 Plochingen, Area of the country garden show 1998.

Plochingen, Area of the country garden show 1998 (23 KB)


Spider (17 KB)j (latitude) = + 48° 42’ N
l(longitude) = - 9° 25’ E
Type : Spider, Azimuthal sundial, horizontal
Time display : Standard time (Arabic hours), Universal Time
Shortes intervals markes : 1/2 hours
Artistic style : Artistically
Material : concrete, high-grade steel, brass
Artistry and craftsmanship : The circular dial plate has a diameter of 7 m . It is in steps ordered, incipient with the undermost step for the winter up to the highest step for the autumn.
Gnomon : Gnomon (vertical rod, 8 m long)with an arrow on the top in the direction of the Pole Star.
Construction date : 1998
Designer : Yves Opizzo, Haigersloch, Schwarzwald, Germany
Reference : Zenkert Arnold :"Faszination Sonnenuhr", Kapitel 3.6.1. Sonnenuhrenspinne.
Internet :
DGC-Number : 10731

Remark :

Spider, Azimuthal sundial, without EoT (17 KB) The sundial consists of a Gnomon and a circular dial plate with snakelike hour lines. One reading of the time you need the date . The date is represented by the circles. One recognizes four circle segments. The circle segments are arranged in steps. Every segment corresponds a season (from inside to the outside : Winter, spring, summer, autumn). Every segment is divided into three sections. Every circle is transition with that from a sign of the zodiac to the different one. (the signs of the zodiac are besides this written up the TK symbols) at every circle segment. The vertical gnomon throws a shadow according to the respective azimuth of the sun about the dial plate. One can read the time (standard time (Central European Time-CET or UT) at the intersection point of the shadow of the stick with the respective date. A sundial of this manner called also azimuthal sundial alone the azimuth of the sun is used for the designation of the tense of a verb. An arrow which points to the Pole Star is put on the Gnomon. If the shadow of the arrow corresponds to the shadow of the vertical shade stick, the 'true noon' is shown at the location of the sundial i.e. the sun cuts the place meridian.

Example of the reading :

Spider, Azimuthal sundial, with EoT (17 KB) Adopted we have April 21st. In above picture (drawing) the circle cuts of April 21st the shadow of the stick for 13:30 = 12:30 UT. (for 1st brass plates, in the spring ring i.e. 2nd level).

The Principle of the construction

 If the reading of the time of day is carried out with a shade stick on a dial plate, then this stick must show a grounding axially parallel situation. Vertical gnomons are only possible when one forms this stick mobilely and makes the stick situation dependent on the date. One calls this typ of sundial Analemmatic sundial. One is a rigid vertical stick possibly at the so-called sundial - spides. The hour lines are designed according to the respective azimuthal angle of the sun. A reading of the time then can be carried out only in that circle which corresponds to the date. One can design spiders for the solar time or for the mean time. A drawing of a spider with hour lines for the standard meridian (15th longitude eastern of Greenwich) without of the Equation of Time. The construction was carried out with the help of a programme of F.J. de Vries, Eindhoven. The order of the months goes from the January till December of the outside to inside.

Last update : 23. September 2006