ARA· PACIS· AVGVSTAE: AN ASTRO-ARCHAEOLOGICAL ANALYSIS

Abstract

The Ara Pacis Augustae (Altar of Augustan Peace) is examined as a shrine of light consistent with the astroorientation principles of Roman architect Vitruvius (c.25 BC). Italian archaeologists excavated (1937-38) and relocated the altar along Rome‟s Tiber River – rotating it 75º counter-clockwise from the original orientation. While its magnificent marble sculpture may be viewed at the Museo dell’Ara Pacis, a key astronomical component of the altar‟s architectural design has until now remained encoded on a paper site map. The author calculated the horizon declination (+11.3º decl.) of the altar‟s original northeast opening with Program STONEHENGE (Hawkins 1983, 328-330), Guglielmo Gatti‟s 1938 site map, and Google Earth satellite imagery: True Azimuth ≈ 75º; Latitude/Longitude = 41° 54‟ 10.47” N/12° 28‟ 44.60” E; Elevation ≈ 10 meters ASL; and Horizon Altitude ≈ +1.1º. The Ara Pacis was dedicated in 9 BC (Moretti 1947,7). Analysis shows that the axis of the Ara Pacis enclosure‟s northeast opening originally was oriented to the rising Sun (+11.0º decl.) on both April 21st and August 27th. However, the iconography of the Ara Pacis supports an interpretation that only the April 21st sunrise orientation was intended, because each sculptural element of the Tellus frieze (young woman, flowing amphora, pair of fishes, ram, bull, infant twins) uniquely mirrors the astronomy: Venus (Morning Star phase) and the Zodiac constellations Aquarius-Pisces-Aries-TaurusGemini at dawn on the festival of Par ilia (Pales, goddess of shepherds), 21 April 9 BC. This month and day coincide with the founding of Rome on 21 April 1 ab urbe condita (a.u.c) as recorded by Roman historian Marcus Terentius Varro. The dedication year of 9 BC coincides with the 93rd iteration of the eight-year EarthVenus Synodic Period when Venus also appeared as Morning Star on the first Dies Natalis Romae, 21 April 753 BC.