The latest articles on DEV Community by TianJi Astrology (@tianji-astrology). https://dev.to/tianji-astrology https://media2.dev.to/dynamic/image/width=90,height=90,fit=cover,gravity=auto,format=auto/https:%2F%2Fdev-to-uploads.s3.us-east-2.amazonaws.com%2Fuploads%2Fuser%2Fprofile_image%2F4100017%2Faef4d3b6-4f68-43e6-9a37-5a8c21466f9c.png https://dev.to/tianji-astrology en TianJi Astrology Sat, 29 Aug 2026 13:51:39 +0000 https://dev.to/tianji-astrology/building-an-astrology-engine-ephemerides-aspect-math-and-where-llms-actually-fit-ccm https://dev.to/tianji-astrology/building-an-astrology-engine-ephemerides-aspect-math-and-where-llms-actually-fit-ccm <p>Astrology software looks like it should be trivial — dates and planet positions — until you meet the actual numerics. Building TianJi's chart engine taught us where the hard parts live.</p> <p><strong>Ephemeris first.</strong> You need planet positions accurate to arcminutes across decades. You either embed VSOP87 (analytic, ~200KB of series coefficients) or call Swiss Ephemeris (precise, native dependency). We embedded a compact analytic series: fast, dependency-free, accurate enough for house cusp and aspect work.</p> <p><strong>Aspects are a tolerance-search problem.</strong> A trine is a 120° separation with an orb (tolerance) of, say, 6°. Naively you compare all planet pairs — fine for 10 bodies. Add centaurs and asteroids and you're comparing 30+ bodies across time ranges to find when an aspect becomes exact. The interesting version is inverting the question: "when does this aspect next perfect?" — which becomes a root-finding problem over the ephemeris.</p> <p><strong>Timezones and birth data.</strong> Birth time in 1987 in a city whose timezone rules changed twice since. Historical tz data (with LMT fallbacks for pre-standardization towns) is non-negotiable, or every ascendant is wrong by degrees.</p> <p><strong>Where LLMs fit — and don't.</strong> The model does not compute charts; it interprets them. We hand it the structured chart (verified by the engine) plus the user's question, and it produces the reading. Hallucination risk is contained by making the numeric layer authoritative: the LLM never generates positions, only prose about positions that already exist.</p> <p>That split — deterministic math core, generative language shell — is the architecture we'd recommend for any "AI + domain" product where the domain has exact facts.</p> <p>TianJi puts this in an app with daily transits, natal charts, and AI readings.</p> typescript astronomy ai algorithms TianJi Astrology Sat, 29 Aug 2026 10:38:51 +0000 https://dev.to/tianji-astrology/tianji-chinese-astrology-bazi-decoded-in-plain-english-26ck https://dev.to/tianji-astrology/tianji-chinese-astrology-bazi-decoded-in-plain-english-26ck <p>If you have ever tried to read a BaZi (Chinese Four Pillars) chart, you know the problem: it is a 2,000-year-old system written for classical scholars, not for modern readers.</p> <p><strong>TianJi exists to fix that.</strong></p> <h2> What TianJi does </h2> <p>TianJi reads your birth date and time into a full Four Pillars chart, then translates it into plain English: your Day Master, elemental strengths, current luck pillar, and what this year's energies actually mean for career, relationships, and health.</p> <p>No memorizing Heavenly Stems. No guessing what "weak Wood" implies. Just clear, direct answers.</p> <h2> Built on classical rules, delivered by AI </h2> <p>Every reading is grounded in traditional BaZi logic — the same rules a classical practitioner would apply — but explained the way a good teacher would: simply, with context, and without mysticism-for-mysticism's-sake.</p> <h2> Try it </h2> <p>Free daily insight and full chart readings are available now at <a href="https://tianji-astrology.com" rel="noopener noreferrer">tianji-astrology.com</a>. An Android app is on the way.</p> <p>Questions about your chart? Drop them in the comments — we read everything.</p> astrology ai zodiac