Big clock
The expression Big Clock (or Whole Clock , Whole Pointer ) is used to describe a clock that represents the full day (day and night, the Nychthemeron ).
In Italy, with the large clock ( Italian clock ), a delimitation of the hour counting with temporal hours was established, when one began to count from one to twenty-four for the full day with equinox hours instead of separately for day and night .
It was in contrast to the later introduced small clock (2 times 12 hour counting), which again counts twice from one to twelve, but with equinox hours and each time with a full circle of hands.
Today, the term large clock is only used for counting from 1 to 24 (standardized 24-hour counting ).
The first large clocks were constructed in the Renaissance using the Italian hour counting from sunset , which was traditionally passed down by the Arabs , and which north of the Alps also became known as the Bohemian hour counting . On the Prague clock (see illustration), the outer ring is automatically set over the year to show 24 Bohemian hours .
The Nuremberg clock was also called the large clock in the area where it was used . It should be noted that with the Nuremberg Hours, the separation between day and night was maintained.
Big clock : Astronomical clock at the Prague City Hall
On the Prague clock, the outer ring is automatically set over the year so that 24 Bohemian hours are displayed: here around 5:30 p.m. Inside a fixed scale with 2 times 12-hour display. |
Large clock and small clock : Astronomical clock in Ulm
It contains a small clock in a coaxial arrangement with the 24-hour clock : outer ring and long hand with hand that turns twice as fast. |
literature
- David Gehrig: Investigating the Astronomical Clock of Prague. In: The Mathematica Journal, 7 (2000), 4, 559-562.
Individual evidence
- ↑ Cf. Gerhard Dohrn-van Rossum : The history of the hour. Hanser, Munich 1992, ISBN 3-446-16046-9 , p. 111 f.
