TEMPUS MUNDI - The universal teaching model for explaining the time measurement with the sun


Helios Sonnenuhren
Dr.-Ing. Carlo Heller
True solar time, standard time, summer time, other time zones, noon position of the sun, date, equation of time, sun declination
Dibond, stainless steel, plastics
D350mm x H500mm
4 kg
Equatorial sundial with equation of time diopter. Astronomical teaching model to explain the time measurement with the Sun. World clock for every location in the northern or southern hemisphere.
995,00 € incl. VAT
delivery time 3 weeks
  • 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


The equatorial sundial TEMPUS MUNDI has been developed by Helios Sundials in close cooperation with Christian Wernli, President of the Swiss Astronomical Society SAG and ETH Zurich, as an astronomical teaching model for explaining time measurement with the sun.

With the sun-styled diopter, the apparent migration of the Sun around the world can be traced in a vivid way. The projected light point is aligned with the equation of time curve (analemma) and indicates where in the world the sun is just reaching its peak (true noon). Depending on the setting, the 360 ​​° rotatable time ring reads the standard time or the summertime (daylight saving time) to the minute. Of course, the local apparent time (LAT) can be read too.

TEMPUS MUNDI is a world clock: not only valid in your own country, but also any other time zone can be determined. The equal-area projection of the world contains all time zones of the northern hemisphere and their difference to the universal time (UTC). A southern hemisphere world map with counterclockwise time ring is now available.

The time equation board sits in the fulcrum of the diopter and points to the celestial pole. On the front and the back are the equation of time curves of the ascending sun (winter / spring) and of the descending sun (summer / autumn). Depending on the season, the time equation table is changed over. At the respective time equation curve one can read off the date, the season, the equation of time and the declination of the sun.

The sundial can be set up for any location in the world between 0 ° and 90 ° N (or 0 ° and 90 ° S) with just a few hand movements and without tools. The latitude is set with 0,1 ° accuracy on the vernier scale. The longitude of each northern hemisphere site (or southern hemisphere site) is set at the longitude scale so that the meridian line (north-south direction) passes through the location on the world map.

The footplate stands on three adjustable feet and can be leveled with the aid of two precision spirit levels. An attachment with screws and dowels in the ground is also possible.

On the foot plate a turntable is mounted, which is used for easy alignment of the sundial in north-south direction with the help of the sun and a precise clock.

Material: Dibond (composite material of white painted anodized aluminum and black plastic core) with UV-resistant digital printing. Connecting elements made of stainless steel and plastic. Suitable for permanent outdoor operation. Dimensions: Time ring diameter 350mm, table height (world map) 325 mm, total height about 500mm. Mass: 4kg.

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