As the changing cycle of the moon is the most visible phenomenon, these Vedic Seers or the first astronomer observed the lunar fact that the moon took slightly more than twenty seven nights to complete one revolution in the sky and thus this path of the moon was divided into twenty seven divisions among the cluster of stars. Each of this division [ or lunar mansion] of this cluster of stars was designated as “ NAKSHATRA” [ Sanskrit name of the lunar mansion]. Each Nakshatra (star) was named after the most visible star among that particular star cluster.The ancient Seers also observed that the new moon took place when both the Sun and the Moon stayed in the same Nakshatra and likewise the full moon occurred when the Sun and the Moon remained in the opposing Nakshatra. Each month of a year gets one new moon and one full moon and the name of the month was designated after the name of the most visible star of that Nakshatra where the full moon occurred.

These ancients also observed that the moon took nearly twenty nine and half nights to move from one new moon or full moon to the next, thereby taking 354 days to have 12 new moons or full moons in a year. It must be noted that the first astronomers of India already divided a year into 12 months of 365 days. Thus ,in order to adjust the discrepancy of 11days between the solar year and the lunar year, at the interval of every third year , an extra month [ intercalary month] was added to the lunar year to synchronize with the solar year. Furthermore, the ancient recognized that the earth’s yearly path around the Sun and the moon’s path among the Nakshatras , intersect each other at two points , where the length of the period of the day and night became equal[ equinoxes].The meeting of these two paths happen twice a year : on 21st of march point known as “Vernal equinox”and on 22nd of September, known as “Autumnal equinox”.These two dates are the most important reference points in order to develop a Calendar system. The Vernal equinox is the beginning of the spring [or Vasanta] whereas the autumnal equinox is the first month of the fall term [Sarad]. Hindu rituals begin from the first newmoon following the Vernal equinox and the Autumnal equinox , such as Vasanti puja and Durga puja respectively.

Before independence, the different parts of India followed different Calendar systems, so to standardize the Calendar of India, the first Prime Minister of free India Mr. Nehru, established the Calendar reform committee in 1952 and the renowned astronomer of India Professor Meghnad Saha was selected as its Chairman. Professor Saha along with a few others, did an extensive research on the Calendars of the world as well as the different systems of Calendars of India and submitted their report in 1955 to the Council of Scientific and Industrial Research[ CSIR}.In 1992, CSIR published this report entitled “ History of the Calendar” , which is a valuable document not only about the Indian Calendar systems as well as the Calendars of the World.

Thus “TIME” was the foremost concept which the ancient Vedic Seers tried to interpret and developed the “Hindu Calendar” but still at this age of the scientific progress the understanding of the concept of “TIME” remains as mysterious as before.