The queen of sundials: Long before our modern wristwatches existed, people already appreciated portable timepieces. They used a ring-shaped sundial that they wore on a necklace. The ring sundial from AstroMedia may be a little too large for this purpose, but it is still a real piece of jewellery. It shows its user the true solar time anywhere on earth, provided that the geographical latitude of the location and the month and day are known. Unlike most other sundials, it is not necessary to know the cardinal directions: the ring sundial aligns itself automatically, provided that you know whether it is before or after noon.
The parts of the ring sundial: The rotating suspension shows the position of the zenith, which is directly above the observer, with its reading mark. The opposite lowest point on the half of the celestial sphere that is invisible to us is called the nadir.
The meridian ring indicates the position of the so-called noon line, on which the sun is at its highest point. The hour ring shows the position of the celestial equator, in the centre of which lie the north and south celestial poles. The sun position scale points in the direction of these points with its two ends. The movable pinhole in the sun position scale projects a tiny image of the sun onto the inner edge of the hour ring, where the time is read. Its position on the scale indicates the different declinations of the sun depending on the season.
Dimensions of finished model: 17.5 x 14.5 x 12 cm (H/W/D), folds flat
