According to the Surya-siddhanta, the prathama-sandhya of Kali-yuga lasts 36,000 solar years. Lord Caitanya appeared in the prathama-sandhya after 4,586 solar years of Kali-yuga had passed

Expressions researched:
"According to the Sūrya-siddhānta, the prathama-sandhyā of Kali-yuga lasts 36,000 solar years. Lord Caitanya appeared in the prathama-sandhyā after 4,586 solar years of Kali-yuga had passed"

Sri Caitanya-caritamrta

CC Adi-lila

The prathama-sandhyā and śeṣa-sandhyā, the last division of the preceding age, form the junction of the two ages. According to the Sūrya-siddhānta, the prathama-sandhyā of Kali-yuga lasts 36,000 solar years. Lord Caitanya appeared in the prathama-sandhyā after 4,586 solar years of Kali-yuga had passed.

CC Adi 3.29, Translation and Purport

Thinking thus, the Personality of Godhead, Śrī Kṛṣṇa Himself, descended at Nadia early in the Age of Kali.

The prathama-sandhyā is the beginning of the age. According to astronomical calculation, the age is divided into twelve parts. The first of these twelve divisions is known as the prathama-sandhyā. The prathama-sandhyā and śeṣa-sandhyā, the last division of the preceding age, form the junction of the two ages. According to the Sūrya-siddhānta, the prathama-sandhyā of Kali-yuga lasts 36,000 solar years. Lord Caitanya appeared in the prathama-sandhyā after 4,586 solar years of Kali-yuga had passed.