Sonance for the Precession is a site-specific quadraphonic sound installation created by Neil Leonard, Arthur Levitt, Jr. '52 Artist-in-Residence at Williams College. The electroacoustic composition, played for 30 minutes each day half an hour before sunset, explores ancient ideas connecting the precession, or movement, of the equinox with the harmonic series. The composition provides a context to reflect on how Hindu and Greek theories of astronomy and acoustics developed through intercultural exchange as far back as prehistoric times. The installation plays from the top of Hopkins Observatory, the oldest functioning observatory in the U.S. Sonance for the Precession is presented by Williams College Museum of Art (WCMA).