A Study of Ethnoastronomy in Ciptagelar Civilizations, Sukabumi Regency, West Java, Indonesia: Relation of Full Moon Phase with Javanese Calendar and Hijriyah Calendar

Astronomy Division, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jl. Ganesa 10, Bandung, 40132, Indonesia

^* Corresponding author: mthdw788@gmail.com

Published online: 21 August 2020

Abstract

Astronomy has been practiced for as long as humans have been looking at the sky. Early civilizations used several celestial objects to do their daily activities, like doing a traditional ceremony. Ciptagelar Village is located at Sukabumi Regency, West Java, Indonesia. It has been established for almost 650 years. Ciptagelar villagers consider that a full Moon phase is a special and sacred thing. They have a welcoming ceremony for it, named Mapag Purnama. We study this activity in the way of Ethnoastronomy. The methods that we used are interviewing the villagers, including the customary leader of Ciptagelar Village, and doing a literature study. Ceremony of Mapag Purnama is held every 13^rd to the night of 14^th of the Moon Javanese Calendar. We use three references for choosing the date of full Moon phase, namely Fred Espenak, NASA, and Stellarium application. This date is then converted from Solar Calendar to Javanese and Hijriyah. Because Javanese Calendar is adopted from Hijriyah Calendar, both of two will have the same dates. We use 120-years correction for a difference cycle and number of leap years. However, after 2010 CE this correction is no longer valid. We find that the Javanese Calendar is one day slower than the Hijriyah Calendar.