The cultural meaning of Renaissance debates on ephemerides cannot be restricted to the technical dimension of astronomical computation. Predictive precision was in fact the presupposition for astrological forecasts. Given the intellectual and ethical relevance of astrology in that epoch, a criticism of the reliability of ephemerides invested also the tenability of astrological beliefs, and questioned social and cultural practices linked to it. The interconnection of mathematical-astronomical, astrological, philosophical and ethical issues in debates over heavenly predictions is witnessed by the fierceness of the Turin controversy of 1580-1581 opposing the astrology critique Benedetto Altavilla and the ducal mathematician Giovanni Battista Benedetti. The preprint includes a transcription of selected passages from four Turin publications by these authors as an appendix: Benedetto Altavilla, Animadversiones in Ephemeridas, Taurini, apud haeredes Nicolai Bevilacquae, 1580; idem, Breve discorso intorno gli errori dei calculi astronomici, Turino, appresso gli heredi del Bevilacqua, 1580; idem, In Nome di Dio, broadside (11 August 1581); Giovan Battista Benedetti, Lettera per modo di discorso... all’illustre Bernardo Trotto, intorno ad alcune nuove riprensioni, ed emendazioni, contra alli Calculatori delle Effemeridi, Torino, appresso gl’heredi del Bevilacqua, 1581.