Topics on the History of Tibetan Astronomy With a Focus on Background Knowledge of Eclipse Calculations in the 18th Century
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CitationJo, Sokhyo. 2016. Topics on the History of Tibetan Astronomy With a Focus on Background Knowledge of Eclipse Calculations in the 18th Century. Doctoral dissertation, Harvard University, Graduate School of Arts & Sciences.
AbstractThe eclipse calculations in Tibet feature religious implications. One religious issue is Buddhist chronology (bstan rtsis). With Kālacakra calculational bases, Tibetan Kālacakra astronomers have tried to synchronize with the Buddhist texts, stating that the Buddha’s enlightenment occurred during a lunar eclipse of the full moon. The concept is called “backward calculation” (yar log gi rtsis).
Another religious issue is the rite of poṣadha (gso sbyong). At some point in Tibet, the idea of ūnarātra (zhag mi thub) in the Abhidharma literature was used to argue the accuracy of the weekday (gza’) value of the skar rtsis for the performance of gso sbyong. However, the decision of the accurate day for the gso sbyong during the 18th century Amdo became an issue. At stake was the conjunction with the occurrence of the solar eclipses, whose dates occasionally matched up with the Qing Chinese calendar, not with the skar rtsis calendar. Upon these cases, one of the possible solutions was to perform gso sbyong in conformity with region (yul bstun gso sbyong) according to the Chinese date.
Under the situation that an eclipse is closely tied to the religious chronology and practice, Tibetan astronomers made great efforts to produce the eclipse calculation results which were in accordance with direct experience (mngon sum). However, they have been confronted with the incongruity between their calculations and the real phenomena of an eclipse. Inevitably, the non-Kālacakra methods and knowledge, including observation, empirical data, debates, criticism, research into other traditions, etc. have been incorporated into the skar rtsis system based upon the Kālacakra.
Technically, adding a correction (nur ster), the correction of residual (rtsis ’phro), the correction of a Great Conjunction at the zero point (stong chen ’das lo), etc., within the conceptual and methodological framework of the Kālacakra, have been used to tally calculations with the real phenomena of an eclipse. Also, the non-Kālacakra Chinese Lixiang kaocheng system (later known as Mā yang rgya rtsis), which was based upon modern geometric and trigonometric knowledge, was used.
Citable link to this pagehttp://nrs.harvard.edu/urn-3:HUL.InstRepos:33493606
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