The Vedic calendar is an astronomical calendar based on movements of heavenly bodies (planets, stars and our galaxy). It has no sectarian or communal base as other eras. The Vedic scientific tradition of Kalagananaa (Time calculation) is based upon the science of astronomy. The Vedic Rishis started their calendar as per the location of Bharat (India) on earth. At the early Vedic period the calendar was started from Dakshinayana (Summer solstice) to Dakshinayana (Summer solstice) keeping in view the location of Bharat (India) in the southern hemisphere of the earth. Later when Bharat shifted to the equator, the calendar was started from Vasanta Sampaat (Vernal Equinox) to Vasanta Sampaat (Vernal Equinox) and lastly it was started from Uttarayana (Winter solstice) to Uttarayana due to the shift of Bhartiya (Indian) continent to the northern hemisphere.