The aim of this work is to present new hypotheses concerning a great disk of andesite – approximately 7 m in diameter – which was discovered in Meridional Carpathians in Romania on the sacred terrace of the capital of the ancient kingdom of the Dacians. Having included in this structure all the specific features of a sun dial, the place’s latitude φ, the obliquity of the ecliptic in epoch ε, as well as a north–south orientation, is possible and probable that this is the “discus in planitia” that Vitruvius ascribed to Aristarchus.