Zodiacal Circumference as Graduated in Jaina Astronomy

This technical paper analyses how Jain astronomers divided the celestial circle into quantifiable units. The authors explain that the Jambūdvīpaprajñapti describes the lunar zodiac as a series of twenty‑seven (or twenty‑eight) asterisms whose stretches are measured not in degrees but in muhurtas (each muhurta being forty‑eight minutes). According to the text, six of the naksatras combine with the Moon for fifteen muhurtas, another six for forty‑five muhurtas and the rest for thirty muhurtas each. A table is provided summarising the time‑values of each asterism and showing that the total for a naksatra month is 81 927 muhurtas, equivalent to the Moon’s sidereal revolution. The article demonstrates how these time units were used to graduate the zodiacal circumference and to compute the relative motions of the Sun and Moon during syzygies. Formulas are given for converting the lunar divisions into solar days and for determining the positions of the Sun and Moon at the end of a five‑year cycle. The authors argue that this system reflects a sophisticated understanding of cyclic time and that it predates similar developments in classical Indian astronomy. By comparing Jain values with those of other traditions, the paper suggests that the Jain scheme influenced later Siddhāntic astronomy. The study thus highlights the originality and precision of early Jain cosmography.

Summary reviewed by a volunteer editor.