By Swami Harshananada
From the most ancient times, all religious activities were performed at times considered auspicious or suitable for them. Calculations were done based on the movements of the Sun, the Moon, the planets and the stars. This resulted in the growth of an entire science of Vedic Astronomy called as ‘Vedāṅga Jyotiṣa’.
The most fundamental periods of time, common to all the nations are the day, the month and the year.
- The day is due to the revolution of the Earth round its axis.
- The month is mainly a lunar phenomenon based on the waxing and waning of the moon.
- The year is due to the apparent motion of the sun as seen from the Earth.
Hence a luni-solar calendar from the ancient times is being followed. Due to the two ways of calculating, there occurs a difference. Hence a necessary adjustment is to be made to bring the two into consonance. The lunar year on which all the religious activities are based, is less than the solar year by about eleven days. Hence two intercalary months are added in five years, one being a second Āṣāḍha (the 4th lunar month) at the end of 2 V2 years and a second Pauṣa (the 10th lunar month) at the end of another 2 V2 years. This is according to Vedāṅga Jyotiṣa.
Later works give varying periods after which the intercalary month occurs. The general rule seems to be that the lunar month in which no saṅkrānti (apparent movement of the sun from one constellation to the next, as seen from the earth) occurs, is called as an adhikamāsa and bears the same name of the next lunar month which is called śuddha or nija or prākrta, to distinguish it from the former.
Somehow, even from the ancient times, the adhikamāsa was considered inauspicious and hence named malamāsa (‘the dirty month’), malimluca (‘a thief), aiñhaspati (‘the lord of sins’) and so on. During this month one was advised to avoid acts like consecrating Vedic fires, installing images, offering gifts, observing vratas or religious vows, performing upanayana and other samskāras.
- Padma purāṇa 6.64
- The Concise Encyclopedia of Hinduism, Swami Harshananda, Ram Krishna Math, Bangalore