Field notes from the Asterwise team.
How we keep ancient calculation correct, fast and verifiable, and what we learn while building it. Engineering, method, and the occasional product note.
What is an astrology MCP server, and why every AI astrology product needs one
LLMs cannot compute planetary positions; they approximate them from training data. For Jyotish calculation, that distinction has real consequences. Here's what an MCP server changes.
# claude connects, then calls real math mcp add asterwise \ https://mcp.asterwise.com/mcp # → OAuth 2.1 · scope asterwise:read # → 103 tools, backed by Swiss Ephemeris tools.call("natal", { ... }) # arc-second, signed, deterministic
Build a daily panchanga bot with n8n, no code
A schedule trigger, one Asterwise node, and a formatted message, with a real verified run: tithi, nakshatra, weekday, yoga and karana, every morning.
TutorialAdd Vedic matchmaking to a Next.js app in 30 minutes
One server action, one form, no key in the browser. Ashtakoot out of 36 with Rajju and Vedha shown as vetoes, from the TypeScript SDK, with a working repo.
MethodologyChecked against NASA JPL Horizons: 80 positions, 1950 to 2050
Asterwise longitudes next to JPL Horizons, which shares no code with the Swiss Ephemeris. Median difference 0.046 arcseconds, raw data and a script to reproduce it.
MethodologyVerified against Swiss Ephemeris: the reference chart
One reference birth, every planet, the ascendant, the ayanamsa and a day's panchanga from Asterwise, placed next to an independent Swiss Ephemeris run. Plus the same chart cast inside Claude.
Deep DiveThe five levels of Vimshottari Dasha, and why two is the common cap
Vimshottari defines five nested time periods. Many implementations return two. The difference between a 17-year window and a 3-day window is the entire timing system.
MethodologyRajju and Vedha as hard vetoes: why they are not part of the Guna Milan score
Many implementations fold Rajju and Vedha into the score as penalties. Classical texts treat them as conditions prior to the score. Why that architectural distinction matters.
Deep DiveBhava Chalit and Rashi house: why every planet has two house positions
A planet near a cusp occupies one house by sign and a different one by spatial position. Both are correct; they answer different questions. Many implementations return only one.
MethodologyCombustion and deep combustion: why they are two fields, not one
Classical Jyotish describes two distinct states of solar proximity. Many implementations return one boolean, collapsing a distinction the tradition treats as meaningful.