Article of the month October

Time system conversion, part 2

Article of the month for August shows a modern time system conversion graph.
Such graphs are not new, and already featured on card dials from the 16th century.

Below is a copy of an example by Johan Stab.
The first figure shows apparent solar time and Babylonian and Italian hours.
The second figure shows antique hours separately, for clarity. In reality, both figures were merged into one.

Peter Apian, or Petrus Apianus or Peter Bienewietz, made different card dials, but these also had a conversion graph.
The figure is a copy of one of his card dials, without the antique hours.
Below is a photograph of an actual card dial.
Notice how in the photograph of the Apian card dial the antique hour lines are different from what they should be.
Apian attempted to draw planetary hour lines, and these differ from antique hour lines.