Of 31 and 30, and 28 as well…

Yesterday I had written about how to read a Panchāngam, or Hindu calendar.

Today, we look at a few more interesting concepts.

While we normally follow the Gregorian calendar in our daily lives, the Panchāngam holds a special significance. The Gregorian is quite arbitrary, with months having 30 or 31 days with no apparent logic, and the New Year coming in on 1st of January – a happy occasion bang in the middle of winter.

By the way, did you know that till the mid 1700s, New Year was celebrated on 25th March? That made more sense, given the onset of spring and the rejuvenation all around in Mother Nature. In India, we still celebrate new year in the first fortnight of April…

वेद मासो धृतव्रतो द्वादश प्रजावतः । वेदा य उपजायते ॥

veda māso dhṛtavrato dvādaśa prajāvataḥ | vedā ya upajāyate ||

An allusion to the thirteenth, the supplementary or intercalary month of the Hindu unisolar year and to the transition to the lunar year from the solar year; ‘that thirteenth or additional month which is produced of itself, in connection with the year, yaḥ trayodaśo adhikamāsa upajāyate saṃvatsarasamīpe svayam evotpadyate.

The above is mentioned in the Rig Veda, which alludes to the 13th month (adikā māsā) that is inserted every two and a half years or so, to compensate for the irregularities between the solar and lunar years. This is why all our festivals retain their positions in the solar year – else Diwali would end up coming in January in the scheme of things!

A lunar month is divided into 30 lunar days. Lunar days in the Indian calendar are called tithis. They, too, are calculated very scientifically using the difference of the longitudinal angle between the position of the sun and the moon.

Each tithi is defined by the time required for the longitude of the Moon to increase by 12° over the longitude of the sun. The Vedic astronomers had knowledge the orbit of the moon around the earth was elliptical and calculated the duration of each lunar day(or tithi).

The length of a tithi was allowed to vary in length from about 20 hours to nearly 27 hours. That is why we find at certain times, a tithi being ‘omitted’, and at certain times, two consecutive days sharing the same tithi.

In the Indian calendar, the month follows the phases of the moon. The interval between two consecutive new moons (no moon) or full moons was the basis of calculating the length of a month. Two systems of month-reckoning were prevalent in different parts of India at different times: the Purnimanta system — in which the month ends with a full moon; and the Amasanta system — in which the month ends with a ‘no moon’ night.

Each month is divided into two parts or pakshas- the Shukla paksha and the Krishna paksha. When the moon waxes from new moon to full moon, it is the Shukla paksha (light lunar fortnight). When the moon wanes from the full moon to the new moon, it is the Krishna paksha (dark lunar fortnight).

Each paksha is consisting of 15 Tithis. The first day of Shukla paksha starts with Amavasya (‘no moon’) and reaches Purnima (full moon) on the 15th tithi, thereafter starts the first day of Krishna paksha, which ends in new moon on 15th tithi of Krishna paksh. This system of dissecting a month equally into two, and again into 15, is a truly ingenious, logical and simple.

I will try to add more such details on our calendar system in the coming days. Indians maintained an elaborate system of time – much more detailed than our present time calculation systems. Such ingenuity should be appreciated, and learned by kids in school so that they know that our forefathers have left us a treasure that we so easily tend to forget…

See you tomorrow!