The position of the moon in Thai culture is divided into 27 sections according to sidereal period using reference from fixed stars. These fixed stars have 27 groups, called the lunar mansions. The days of full moon in some lunar mansions were assigned to the Buddhist holy days such as Magha Puja, Visakah Puja and Asalha Puja. It was found that before the Adhikamasa year and in the Adhikamasa year, the events of full moon may not match with the Buddhist holy days on the Thai Lunar calendar. This is due to the fact that the Thai lunar calendar was adjusted to match the solar calendar and the real lunar month. This effects the position change of the full moon in the Lunar Mansions.
Keyword: Lunar mansions, Lunar month, Thai Lunar calendar, Adhikamasa year, Buddhist holy days