AbstractWe demonstrate that column Φ in System A of the Babylonian moon ephemerides can be derived from such horizontal phenomena as were observed and recorded by the Babylonians. Combining four of the so‐called ‘Lunar Six’ in such a way that the effects of the oblique ascension are eliminated, we obtain a curve which oscillates, indeed, with the exact period and the approximate amplitude of Φ. Our curve (which we call S̀) also contains oscillations with the approximate period of the Saros and allows us to find the period relation which is underlying column Φ. Herewith it has been shown for the first time that the length of the anomalistic month can be derived from horizontal obs