Identifying a possible founding date of Chiang Mai by simulating the star positions from Chiang Mai’s natal chart using astronomical software

Abstract

Chiang Mai’s natal chart represented the founding date using an ancient astrological method. It showed the positions of Sun, Moon, Mars, Mercury, Jupiter, Venus, Saturn, Ascendant, and Rahu within the boundaries of the 12 zodiacal constellations. This study aimed to determine a possible Chiang Mai’s founding date by simulating the positions of those stars using the astronomical planetarium software “Stellarium”. We first identified the ecliptic longitude of the boundaries of the 12 zodiacal constellations according to the J2000 Astronomical Standard. Then we created a database of the times at which Jupiter and Saturn were in each zodiac throughout the history of Chiang Mai, between the years 1043-2043 B.E. (500-1500 A.D.). From the aforementioned analysis, there were ten possible establishing timelines for Chiang Mai. After adjusting Stellarium software during those timelines, the possible founding date of Chiang Mai was on Thursday 12th of April 1839 B.E., at 3:26 to 5:53 AM according to the Gregorian calendar. The result matches the official Chiang Mai’s founding date, with a difference of 7 days. Therefore, this method could help historians estimate the date and time represented in a natal chart for discovering the corresponding historical age. © 2023, Prince of Songkla University. All rights reserved.