ABSTRACT
In this chapter, the authors limit ourselves to an investigation of the tables for calculating planetary longitudes. In order to make an attempt to place the Nasiri zij within the history of Islamic astronomy. The parameters underlying the mean motion tables in the Nasiri zij were estimated by means of the Least Number of Errors Criterion, which determines the range of parameter values for which the largest number of values in a given sub table is correctly recomputed. The parameter lists in Chioniades’ work and in the Sanjufini zij contain a number of daily mean motions expressed to a precision of sexagesimal sixths (rather than fifths). The planetary equations in the Nasiri zij are basically of standard type, except that they are displaced by 12 zodiacal signs. In Ptolemy’s Almagest and Handy Tables, as in practically all Islamic zijes, the lunar and planetary equations of anomaly are calculated by performing so-called “Ptolemaic interpolation”.
