Ritualistic cyclicity in Indo-Greek astral science –

Expressions for various modes of time measurement in the Yavanajātaka

 Astral sciences, mathematics and rituals, Université Paris 7

Mar 19-20, 2015


As a prototypical work of Greco-Indian astral science, the Yavanajātaka, in particular, its last chapter (Ch. 79) on mathematical astronomy, encapsulates some key concepts on time measurements which would later became the mainstream elements in the Indian tradition of jyotiṣa. Some of these key concepts include the large astronomical cycle known as yuga, the smaller cycles of year, season, month, planetary week, day and tithi. What distinguishes the Yavanajātaka from other extant treatises of the first millennium ce, however, is the fluidity of expression of these astronomical cycles in the text, which suggests the ambivalence of the author in his attempt to blend a heterogeneous body of Greek and Indian astronomical and astral concepts, and to express them in a sound, mathematical manner.

Two features of this important chapter which have been overlooked in past studies are: 1) The Indian elements as exemplified by the close resemblance of tithi-based astronomical algorithm and the description of the water clock to those of the Vedāṅgajyotiṣa and the Arthaśāstra respectively;[1] 2) The description of the Lords of year, ayana, season, month, week, day and hour which conclude the chapter before the colophon.

In this presentation, I would like to suggest the expressions of cyclical time-measures in the text have an unexpressed ritualistic character, which lies beyond the scope of the Greco-Indian genethliacal astrology of the preceding 78 chapters. Beside his concern for comprehensiveness, its author Sphujidhvaja was clearly exposed to the ritualistic significance of these various time-measures from different traditions. While the computation of planetary longitude would be essential to the casting of horoscope, the reckoning of days (ahargaṇa) and various “Lords” suggests a synthesis of Greek and Indian rituals which focus on astral worship.

[1] Based on readings from new manuscript [MAK 2013].