Ptolemy's table of chords: Implications considered and discussed

Abstract

Ptolemy's table of chord lengths from the Almagest converted into decimal values and recalculated. Presentation and discussion of Ptolemy's method of calculation and sexagesimal values in comparison to calculations by trigonometric functions with regard to several editors. A significant relationship between the difference values of the two methods and angle number was found: The higher the expansion angle, the greater the overestimation of chord lengths. Implications for early scientific astronomy in context with the development of mathematical methodology are discussed.