According to Jyotir-vedic astrology, when the relationship between the planets and the rulers of these six divisions (sad-varga) is determined, the auspiciousness of the moment of birth can be calculated
(According to the Jyotir-veda, or Vedic astrology, the auspicious birth moment is described as follows:) The moon was in Leo (the figure of the lion in the zodiac), Leo was the ascendant, several planets were strongly positioned, and the ṣaḍ-varga and aṣṭa-varga showed all-auspicious influences.
Śrīla Bhaktisiddhānta Sarasvatī Ṭhākura, who was previously a great astrologer, explains this verse as follows: The ṣaḍ-varga (six divisions) are technically called kṣetra, horā, drekkāṇa, navāṁśa, dvādaśāṁśa and triṁśāṁśa. According to Jyotir-vedic astrology, when the relationship between the planets and the rulers of these six divisions is determined, the auspiciousness of the moment of birth can be calculated. In the book named Bṛhaj-jātaka and other books there are directions for interpreting the movements of the stars and planets. One who knows the process of calculating the aṣṭa-varga (eight divisions) can predict auspicious and inauspicious events. This science is known especially by persons who are called horā-śāstra-vit, or those who know the astrological scriptures. On the strength of astrological calculations from the horā scriptures, Nīlāmbara Cakravartī, the grandfather of Śrī Caitanya Mahāprabhu, had ascertained the auspicious moment when the Lord would appear.