Víctor Pérez Villar wrote: > > Hello, > > I would want to know if somebody knows the analytic form of the "Horary > Curves" of a "Quadrant of Temporary Hours". I know the Geometric method of > construction of these quadrants, and all they suppose, as initial > Hypothesis, that these curves are "straight lines", and this is not > completely certain. > > Víctor P.
Hello Victor, The antique hour lines ( daylight devided in 12 hours ) aren't straight lines, that is correct. At higher latitudes, let's say 50 degrees, this is good to see and the shape is a little like an S. The German scholar Joseph Drecker wrote about these hourlines in his book "Die Theorie der Sonnenuhren", 1925 and he gave analitic formulae. For each hour pair new formalae occur, so for 1 + 11, 2 + 10 and so on. Drecker gives such formulae for several types of dials like on a plane or in a sphere or cone. Even for an horizontal dial the formulae are much to long to write down here. There are power factors of 2, 3, 4, 5, and 6 in it, rather complecated. Try to find a copy of the book of Drecker. Best wishes, Fer. -- Fer J. de Vries [EMAIL PROTECTED] http://www.iaehv.nl/users/ferdv/ lat. 51:30 N long. 5:30 E
