The small table sundial is based on several models from the 17th century. It is based on the principle of the torquetum. The name is usually derived from the Latin torqueo = turn, twist, wind, revolve , sometimes also from turcus, Turkish, which explains the rarer name asTurquetum, Turkish instrument . Torqueta have been in use since the 13th century.
The three most important celestial planes - horizon, celestial equator and ecliptic - are built on top of each other and, with the rotatable ecliptic, allow the celestial movements to be displayed as they appear from the respective observation location. The base plate with the four feet corresponds to the horizon level. It is first placed on a horizontal surface, with the hinge axis at an approximate 90° angle to the north. As a result of the subsequent adjustments, the instrument is inevitably positioned precisely.
The complete description of the instrument as PDF for download
