Shadow panel

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Shadow tables were used to determine the time using the position of the sun .

The history of the shadow tablets can be traced back to Mesopotamia. From there the shadow tablets got to Greece. Only from Greece do we have enough testimonials about how shadow panels worked.

Man himself was the gnomon who measured his shadow length with his feet to find out the hour of the day. That is why Aristophanes can in a play from about 390 BC Write. that under a government of women men would only have to worry about when it was time to go out to eat, for example "when the shadow measures 10 feet." At that time there was no other way of expressing the time of day, because hora did not come to mind until 350 BC. Connected the term hour.

With the knowledge of the hour and the measurement of time through the length of shadows, both inventions began to be connected. The result was the shadow table, which was often put down in the form of a table. Its usage was described in a late Greek source as follows: “Stand up straight on a flat place ... measure the full length of your shadow on the ground with your feet. Compare the number of feet you have for that month with your result and you will find the hour. ”The ancient sources say nothing about the length of the person or the ratio of the length of the person to the length of the foot. Otto Neugebauer , thanks to him the first detailed examination of the material, assumed ratios of 6: 1 or 7: 1.

Neugebauer published existing Roman, Coptic, Ethiopian, Syrian and Armenian sources. Not much is known of the Indian tradition, but we have a hint from Marco Polo that the people in Maabar province only recognize the hours of the day because they count the length of their shadow in feet. David King studied the Islamic shadow tablets, which were copied by the 19th century. They show Greek and Indian influences. He found that in addition to the six or sevenfold gnomon, one of 6½ or 6 2/3 feet was also used there. The medieval shadow tables are in this tradition, be they in Greek or Latin. Although the Latin sources form the largest group, they have only been subjected to extensive scrutiny. The study mentions more than 40 Latin shadow tables in various libraries in Europe, but at least twice that number has to be assumed, especially in the context of calendars. The Latin manuscripts date from the 8th to the 16th century.

Individual evidence

  1. ↑ K. Schaldach: The ancient sundials of Greece. 2006, pp. 7-10.
  2. ^ O. Neugebauer: A History of Ancient Mathematical Astronomy- 1975, p. 739.
  3. ↑ Neugebauer, pp. 736-774, especially p. 739.
  4. ↑ D. King: In Synchrony with the Heavens. 2004, pp. 465-527.
  5. ↑ K. Schaldach: Gli 'schemi delle ombre' nel Medio Evo latino. In: Gnomonica Italiana. 16, 2008, pp. 9-16.