Digital sundial
As digital sundial several different types of be sundial called.
- A sundial with a numeric display
- A sundial with a number band projected over a scale line
- A sundial with discrete imaging facilities
Sundial with numeric display
The time of day is displayed in discrete time using digits .
The digitized display is purely optical with sunlight. With comparable mechanical (for example: folding display) or electronic display instruments (for example: digital clock with LED or LCD time display) the change between two displays is supported by auxiliary energy and is abrupt. In the present case, this is only possible to a lesser extent.
Sundial with projected number band
A band is provided with numbers, bent into a semicircle and arranged parallel to the equator. It arches over a polarized dial. The band is translucent at the places of the digits, or it is translucent itself and contains shading digits. The numbers are projected onto the dial by sunlight . The dial contains only one line on the scale. The time indicated is the number that falls on or near this line. Such a sundial is created by changing elements from a ring-shaped equatorial sundial : the scale with digits becomes a projector, the pole rod becomes a scale line.
Such so-called digital sundials are common. They do not have a pronounced digital display. The change in the display is not sudden, on the contrary: with interpolation , the clock can be read continuously.
Sundial with discrete imaging devices: sunlight receivers in three groups in a column (top picture: foreground); Ends of the light guides in a shady wall (top picture: background and bottom picture)
Sundial with discrete imaging facilities
With one imaging device each, a time-discrete display signal is obtained. In each display device, sunlight is received only in an assigned short time interval and displayed as a light spot. The display change is not abrupt. As a rule, the following spot is slowly becoming lighter, while the previous one only slowly disappears. Because of the large number of imaging devices, such a sundial is more complex than most other types of sundial.
Images of digital sundials
Digital sundial with numeric display
Digital sundial with projecting number band
Sundial with discrete imaging facilities
Individual evidence
- ↑ Sundial with projected number band, cardboard kit [1]
- ↑ Globe sundial with discrete imaging devices on an equatorial ring Archived copy ( memento of the original from March 19, 2012 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
literature
- Siegfried Wetzel: The globe sundials MONDO and MAGELLAN . In: Deutsche Gesellschaft für Chronometrie , annual publication 2006, pp. 235-238, two sundials with discrete imaging devices