I am happy to announce the completion of my essay, "The Lost Calculation: Between India and Tibet". This essay is a brief examination of the Kālacakra Tantra and its implications for astrology (Indian and Tibetan). What has been of interest to me is the Tantra's criticism and correction of the siddhāntic calculations, which amounts to an adjustment of the sidereal calculations to tropical calculations. It is interesting that the Tibetans incorporated Indian astrology (signs, nakshatras, etc.), but adjusted the calculations to a tropical zodiac. Given the tediousness of manual calculations, we must at least be open to considering that they had compelling reasons for doing so.
My purpose in presenting this is not to incite a zodiac debate, as I don't believe polemics have any utility. Rather, I hope the verses of the Tantra will engender an open and positive consideration of astrology, zodiacs, and the implication of cross-cultural exchanges.