Arguably the most enigmatic of the Maya calendar cycles, the 819-day count has challenged modern scholars for decades. Even today it is not completely explained and there are several areas for further research, including its relationship with the synodic periods of the planets visible to the naked eye. Earlier research has demonstrated a four-part, color-directional scheme for the 819-day count such that each of the calendar stations progress in increments of 819 days in cycles of 4 × 819 days. Although prior research has sought to show planetary connections for the 819-day count, its four-part, color-directional scheme is too short to fit well with the synodic periods of the visible planets. By increasing the calendar length to 20 periods of 819-days a pattern emerges in which the synodic periods of all the visible planets commensurate with station points in the larger 819-day calendar.
