Kinematics of Venus in Bhadrabahu Sanhita

Summary

The paper “Kinematics of Venus in Bhadrabahu Sanhita” by Sajjan Singh Lishk examines the treatment of Venus in the Jain canonical work Bhadrabahu Samhita (BBS). It shows that ancient Jain scholars investigated heliacal rising and setting of Venus, dividing the sky into different vithis or lanes associated with lunar mansions (nakṣatras). The author introduces heliacal rising, referencing Assyrian and Vedic calendrical practices to set the context for later Indian astronomy. The article explains that inferior planets like Mercury and Venus become combust twice in their synodic periods and clarifies the difference between heliacal rising and evening setting, noting that Venus may appear as a morning or evening star. It then explores how the BBS lists twenty‑eight nakṣatras and assigns each to specific vithis with given numbers of days during which Venus remains invisible. By adding the zodiacal stretches of these nakṣatras (given in muhūrtas) the lengths of the vithis can be computed, allowing the author to reconstruct the movement of Venus relative to different lunar houses. Tables reproduced from earlier work list each nakṣatra with its zodiacal extent in muhūrtas, enabling comparisons with other ephemerides. The author points out that though the data in BBS are fragmentary, they record the synodic period of Venus and the intervals between heliacal conjunctions, indicating systematic observations by Jain astronomers. The first part of the article situates the study within the broader history of astronomy. Ancient Mesopotamian cultures used stellar calendars with months named for astronomical events. The BBS continues this tradition by coupling the visibility of Venus to specific segments of the lunar zodiac. When Venus enters inferior combustion the planet disappears from the evening sky before conjunction with the Sun and reappears after conjunction as a morning star; the durations of invisibility vary depending on the part of the zodiac where conjunction occurs. Lishk shows that the BBS allocates unequal periods of invisibility to different vithis and suggests that this irregular distribution may reflect empirical observations by Jain astrologers rather than abstract calculations. By analysing the BBS pattern, he derives a table of heliacal risings and settings of Venus corresponding to twelve zodiacal signs—for example, Venus remained invisible for fifteen days when moving through Cancer and Leo, four and a half days in Sagittarius, and two days in Pisces. These values are compared with calculations derived from modern astronomy to test the accuracy of the ancient data. The paper also discusses the possible origin of the BBS system; some passages may have been modified over time or assimilated from Siddhāntic astronomy. Nevertheless, the data preserve distinct features of an old Jaina ephemeris. Lishk emphasises that such tables would have been useful for determining auspicious times for rituals and may reflect a broader Jain interest in astronomy and cosmology. By drawing connections between Jaina texts and astronomical knowledge in other Indian traditions the article underscores the independent contributions of Jain scholars to observational astronomy.