How did Greek astronomical models become part of Sanskrit jyotisa?

Greek astronomical and astrological models were introduced to India following the invasion of Alexander the Great. These foreign models were integrated with existing indigenous traditions to form a sophisticated system of Sanskrit mathematical astronomy and astrology known as jyotisa.1

The transmission of these techniques occurred primarily through Sanskrit translations, such as the Yavanajataka. While Indian scholars adopted Hellenistic systems—including the 12 signs of the zodiac—they adapted them to fit their own cultural and philosophical context. For instance, they replaced the original Hellenistic philosophical underpinnings with concepts of divine revelation and incorporated Indian social structures, such as the varna and caste systems, as well as the theory of reincarnation.2

Furthermore, Indian astrologers expanded upon these models by integrating earlier Vedic elements, such as the nakshatras (lunar mansions), and developing complex methodologies for planetary combinations and subdivisions.2