तन्त्रसार (महामाहेश्वर अभिनवगुप्त - तन्त्रालोक का प्रामाणिक सार-संग्रह सटीक)

xxx The course along which prāṇa and apāna move, measures thirty six digits ( anguli ). It is assumed by the Yogin that the hour, the tithi and other long and short units of time get their rise in prāṇa. It is to be noted here that kriyāśakti which operates externally as kālaśakti in prāṇa, is without any definite form. For this reason whatever shines in prāṇa as kṣaṇa, lava etc., may shine as a year or more than several years. Not only that, they shine and rise in it and terminate in the highest equilibrium. When prāṇa runs the course of two and one fourth of a digit the duration is known as tuṭi. Four of such tuṭis make a prahara. Half of a tuṭi is a sandhyā. The exhaling and the inhaling represent the day and the night. In the same way a month consisting of thirty tithis with the broad divisions of two fortnights, is also assumed by the Yogin to rise in prāṇa. All the tithis from pratipat to amāvasyā and then again from pratipat to purṇimā lie along the course of inhaling and exhaling movemsnt of prāṇa and apāna. The sixteenth consisting of half a tuṭi at the start and another half at the final resting place, is considered to be the sandhyā, the meeting point of the day and the night. These two halves of tuṭis are free from the influence of Time, for this reason sandhyās are considered to be very auspicious. Similarty during the dark fortnight the moon or the apāna offers its digits ( kalā ) one by one to prāṇa, the sun and the final one is offered near the dvādaśānta at the fifteenth tuṭi, after which the moon gets itself dissolved in the sun. This is known as amāvasyā when the moon remains latent in the kalā known as amā. The span which is one half of the tuṭi is occupied by amāvasyā and the remaining half is the duration for pratipat. When on