PIETRA Solar ring made of artificial sandstone

PIETRA Solar Ring 200

Helios Sonnenuhren
Dr.-Ing. Carlo Heller
solar time
artificial sandstone
D200mm x B165mm
Solar ring made of artificial sandstone. Diameter 200mm. Display of solar time (LAT) with hour scale calculated for the location. CET-LAT scale or any other standard time-LAT scale. Coordinates are determined from the address data.
695,00 € incl. VAT
5 weeks

Product-Variations and Add-ons
PIETRA Solar Ring 300

  • Shipping costs included in Germany, EU and Switzerland on any order of 100 Euro or above
  • Low price shipping outside the EU by registered letter
  • 2 weeks statutory right of return (customised products excluded)
  • Hotline: +49-611-185 11 06


As if carved in stone!

Sundials made of sandstone have a long tradition in sundial construction. The demanding and time-consuming work of the stone sculptor naturally has its appropriate price, which makes sundial lovers dig deep into their pockets. We now offer an affordable alternative made of artificial sandstone. The sundial is built up layer by layer from sand using the 3D printing process and then infiltrated with epoxy resin, giving the object enormous strength. The edges are also much more stable than those of natural sandstone, and "crumbling" is completely avoided. Finally, the sundial receives a coating of polyurethane matt varnish, which makes the surface resistant to dirt and hand perspiration. This also makes cleaning with chemical agents possible.

In this large version with an outer diameter of 200 mm or 300 mm, the PIETRA solar ring is a precise instrument that does not require any compass. The time and date scale is precisely calculated for the geographical coordinates of the location. The light spot projected inside shows the true solar time. On the outside, a table is engraved from which you can take the daily difference between Central European Time (CET) and the true solar time. Add this value to the solar time you read and you will get the exact CET. Also possible for other time zones!

The solar ring can be made for any place in the world between 23° and 66° north or south latitude. The coordinates and the location are engraved.If desired, it is also possible to inscribe the base with your own name, a motto or a congratulatory message.

It doesn't get any more precise than this!

We have improved the solar ring in a number of points so that, in conjunction with the exact manufacturing process, maximum accuracy can be expected.Among other things, the refraction of the sun's rays in the earth's atmosphere and the lengthening of the ray path due to the deflection from the central plane are taken into account.  An important improvement is the linear date scale, which is clearly divided into two halves (1 April - 30 September and 1 October - 30 March). In conventional constructions of the Farmer's Ring, the date scale is based on the declination of the sun. This results in a date scale that becomes narrower and narrower in the direction of the solstices, making it almost impossible to set the date accurately.  When using only a year-round scale, the date division with the signs of the zodiac is also necessary, which further complicates the setting.

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