The math we use
In plain terms: we use the same astronomical engine that NASA and professional astrologers use, so every planet in your chart is placed exactly where the sky actually has it.
Under the hood, Jyotish uses the Swiss Ephemeris (v2.10.03) — the same library behind JHora, Parashara's Light, and Kala. Swiss Ephemeris fits its long-range tables to the VSOP87 planetary theory and JPL DE431 for the Moon, identical to the models used by NASA mission planners.
For your birth moment, we compute:
- Geocentric ecliptic longitudes for Sun, Moon, Mars, Mercury, Jupiter, Venus, Saturn
- True Rahu and Ketu (mean node available as an option)
- Ascendant and Midheaven from your exact birth coordinates
- All 27 nakshatras and 108 padas
- Sub-divisional charts (D-1 Rasi, D-9 Navamsa, D-10 Dashamsa, D-12, D-16, D-24, D-30, D-60)
Ayanamsa — why we default to Lahiri
Plain take: the ayanamsa is the offset we use to translate "tropical" (season-based) positions into "sidereal" (star-based) Vedic positions. We default to the most widely-accepted value so your chart matches what a classical jyotishi would produce.
Picking an ayanamsa changes every sign placement in your chart, so we are deliberately explicit about which one we use. Jyotish defaults to Lahiri (Chitrapaksha), the official ayanamsa of the Indian Government's Rashtriya Panchang since 1955, and the standard taught in most modern Jyotisha institutions.
You can switch to another ayanamsa at any time in Settings — all scores recompute instantly, and each view is labelled with the value in use.
House system — why we use Whole Sign by default
Plain take: each sign is one house. Clean, classical, and consistent at any latitude on Earth.
Whole Sign is the oldest documented house system in both Vedic (Parashara) and Hellenistic traditions. It is simple, symmetric, and — critically — does not distort near the poles the way quadrant systems do.
Sripathi bhava-chalita (overlay bhava cusps) and KP sub-lord divisions are available in the Chart view for advanced users. We never mix systems within a single score — if you change the default, every affected score is re-labelled so you know exactly what was recomputed.
Vimshottari Dasha — how the 120-year cycle works
Plain take: your life runs through a fixed 120-year sequence of planetary periods. Knowing which period you're in right now is half the reason a daily score is useful.
Vimshottari is the ruling dasha system in Parashari jyotisha. Every person moves through a 120-year cycle of nine planetary periods, starting from the nakshatra lord of the Moon at birth. Each Mahadasha subdivides into nine Antardashas, each of those into nine Pratyantaradashas, and so on down to Sookshma level.
| Dasha lord | Years | Share |
|---|---|---|
| Ketu | 7 | 5.83% |
| Venus | 20 | 16.67% |
| Sun | 6 | 5.00% |
| Moon | 10 | 8.33% |
| Mars | 7 | 5.83% |
| Rahu | 18 | 15.00% |
| Jupiter (active) | 16 | 13.33% |
| Saturn | 19 | 15.83% |
| Mercury | 17 | 14.17% |
Aarav's current stack
Aarav was born with the Moon in Mrigashira nakshatra (Mars-ruled). His dasha began from Mars and has progressed through Rahu to Jupiter. Right now, Jyotish reads three nested periods simultaneously:
How we score each day — the 8-category methodology
Plain take: every day gets eight independent scores (0–100), built from a fixed six-step procedure. No hand-written "vibe" overrides, ever.
This means two things matter to you: scores are reproducible (you'll get the same number tomorrow for today), and they're auditable (every rule is written down).
The 8 categories and what drives them
Why our scores are deterministic
Plain take: run the same birth data through Jyotish today, next week, or in 2040 — you'll get the exact same number, to the decimal.
There is no randomness, no A/B testing of your horoscope, and no "model drift" as we update the AI layer around the numbers.
name: "Aarav Sharma",
date: "1990-06-15",
time: "10:30 IST",
place: "Delhi, IN",
ayanamsa: "lahiri",
for_date: "2026-05-19"
}
wealth: 78, love: 62,
pace: 71, focus: 84,
emotional: 59, social: 66,
caution: 28, spiritual: 73,
hash: "a4f2e9...3d1b"
}
What the AI does (and what it doesn't)
Plain take: the AI only helps explain the numbers in friendly language. It never produces or changes a score.
Jyotish uses a large language model (currently Claude, with an OpenRouter fallback) for the chat and for the 1–2 line explanatory prose on the Day view. The AI receives scores and facts as structured input, and translates them into plain English — nothing more.
The AI does
- Explain what "Jupiter conjunct natal Moon" means in plain English
- Answer follow-up questions about your chart
- Phrase the daily "best use" and "gentle caution" sentences
- Translate Sanskrit terms on request
The AI never
- Invents a score, changes a score, or rounds a score
- Picks a dasha period or ayanamsa value
- Decides what's "favourable" or "challenging" on its own
- Remembers content between sessions unless you save it