Ptolemy’s table has the chords for every possible angle in ½° increments (360 table entries in all), to 3 sexagesimal digits of precision, or about 5.5 decimal

Ptolemy’s table has the chords for every possible angle in ½° increments (360 table entries in all), to 3 sexagesimal digits of precision, or about 5.5 decimal digits of precision. It also had an additional column showing the derivative of the chord function at each ½° at 5 sexagesimal digits of precision, for use interpolating at arbitrary angles in between the listed ½° increments. https://en.wikipedia.org/wiki/Ptolemy%27s_table_of_chords https://en.wikipedia.org/wiki/Ptolemy%27s_table_of_chords You might be thinking of Hipparchus’s table (from a few centuries earlier) which only had multiples of 7½°.