yadā vṛścikādiṣu pañcasu vartate tadāho-rātrāṇi viparyayāṇi bhavanti.

etena hi divo maṇḍala-mānaṁ tad-vida upadiśanti yathā dvi-dalayor niṣpāvādīnāṁ te antareṇāntarikṣaṁ tad-ubhaya-sandhitam.

By the dimensions of Bhū-maṇḍala experts indicate the dimension of the sky about the earth. They are like two halves of a bean seed. Antarikṣa joins the two together.

Niṣpāva is a type of been, ādīnām indicates less specific seeds. Just as by seeing the dimension of one of the halves of the seed one can understand the dimension of the other half, one should consider the dimension of the earthly sphere[50] and the heavenly sphere to be the same. Between them is the antarīkṣa, measuring 200,000 yojanas. It is joined to them on both its sides.

|| 5.21.3 ||

yan-madhya-gato bhagavāṁs tapatāṁ patis tapana ātapena tri-lokīṁ pratapaty avabhāsayaty ātma-bhāsā sa eṣa udagayana-dakṣiṇāyana-vaiṣuvata-saṁjñābhir māndya-śaighrya-samānābhir gatibhir ārohaṇāvarohaṇa-samāna-sthāneṣu yathā-savanam abhipadyamāno makarādiṣu rāśiṣv aho-rātrāṇi dīrgha-hrasva-samānāni vidhatte.

Situated in the middle of the antarīkṣa, the sun, master of heat, heats up and lights up the three worlds by its light. The sun moves slowing during uttarāyaṇa, ascending, moving through six zodiac signs starting from Capricorn, making the days long and the nights short. It moves quickly during dakṣiṇāyana, descending, moving through six zodiac signs starting with Cancer, making the days short and the nights long. It move at medium speed during the equinoxes, neither between ascending and descending, moving through Aries and Libra, making the days and nights equal.

The sun is situated in the middle of the antarīkṣa. During uttarāyaṇa (udagayana), by slow speed while ascending in the sky and passing time, the sun moves through six zodiac signs starting from Capricorn, making the days gradually longer and the nights shorter. During dakṣiṇāyana, moving with quick speed and descending, the sun moves through six zodiac signs starting from Cancer, making the days shorter and the nights longer. By moving at medium speed during the equinox periods, with days and nights equal, the sun moves through Aries and Libra.

 

|| 5.21.4 ||

yadā meṣa-tulayor vartate tadāho-rātrāṇi samānāni bhavanti yadā vṛṣabhādiṣu pañcasu ca rāśiṣu carati tadāhāny eva vardhante hrasati ca māsi māsy ekaikā ghaṭikā rātriṣu.

When the sun is Aries and Libra, the days and nights are equal. When the sun moves in Taurus and the five following signs, the days increase in length and then decrease every month by a ghaṭikā.

This verse further explains. Because there is no extreme difference in the day and night during this time, it is called equal. Complete equality will only take place on one day and night of the month. When the sun is in Taurus and Gemini the days increase in duration, and when the sun is in Cancer and the following months, the days become shorter, whereas the nights become longer. When the nights increase in duration, the days become shorter. But actually, starting from Capricorn the days become longer and starting from Cancer, the days become shorter. This will later be clearly explained. The statement that the days increase by ghaṭikā each month is a general statement, since the increase and decrease is different each month.

|| 5.21.5 ||