This animation illustrates the [url=http://articles.adsabs.harvard.edu/cgi-bin/nph-iarticle_query?bibcode=1967AJ.....72..964N&db_key=AST&page_ind=0&plate_select=NO&data_type=GIF&type=SCREEN_GIF&classic=YES]zigzag function used in ancient Babylonian astronomy[/url] to predict the conjunctions of the Moon and the Sun (i.e. synodic periods in a lunisolar calendar). The data is sourced from The Exact Sciences in Antiquity by O. Neugebauer who in turn deciphered them from cuneiform tablets dated 133-132 BC.[br][br]The left hand graphics illustrates the motion of the Sun and the Moon. While the Sun moves through an arc of around 28/29 degrees on its orbits, the Moon should be understood to complete one revolution around the Earth and some more before the next conjunction.[br][br]The right hand graph plots the extent of the Sun's movement between two conjunctions. This increases / decreases by 0.3 degrees (18 arc minutes) between successive conjunctions.