A Study of the Astronomical Alignment of Prang Ku Monuments in Chaiyaphum Province with Solar Movements

Abstract

This research aims (1) to study the orientation of Prang Ku Monuments in Chaiyaphum Province using digital mapping software, and (2) to determine the dates when the rising and setting of the sun aligns with the doors of the Prang Ku by calculating the declination of the sun. The azimuth angles of the Prang Ku monuments were measured in relation to longitude using the digital mapping software. These azimuth angles and the geographic latitudes of the Prang Ku locations, were used to calculate the sun’s declination in order to identify the dates when the sunrise aligns with the doorways of the Monuments. The study revealed that only four Prang Ku monuments in Chaiyaphum Province exist in a relatively intact state. These structures are oriented along an east-west axis and face slightly northeast, corresponding with the sunrise that aligns with the doorway in April and September, during which the sun enters the zodiac sign of Aries according to the Maha Sakaraj calendar, marking the solar New Year or Thaloeng Sok, which adds another year to the calendar cycle influenced by Indian culture that got adopted by the Khmer Empire. These structures may have been built as ancient instruments for dividing time and seasons, functioned as an ancient calendar. Studying the orientation of the Prang Ku monuments reveals the wisdom of ancient builders in designing architecture that utilizes the position of the sun to determine optimum orientation, aligning functional space use with astronomical events.