How Vedic Horā computes
Nothing here is a trade secret. If a reading tells you something, you are entitled to know exactly which astronomy produced it and exactly which text authorised it. This page is that answer, in full.
The two layers
Horā is deliberately split in two, and the halves never bleed into each other. Gaṇita is astronomy and only astronomy. Phala is classical interpretation and only that. A bug in one cannot silently invent a result in the other.
Gaṇita — the astronomy
| Ephemeris | A high-precision analytical ephemeris — no external data files required. |
|---|---|
| Zodiac | Sidereal, with the Lāhirī (Citrapakṣa) ayanāṁśa — the Indian government standard and the norm in Vedic practice. |
| Bhāvas | Whole-sign houses, following the Bṛhat Parāśara Horā Śāstra. The sign containing the lagna is the first bhāva entire. |
| Nodes | Rāhu and Ketu as a diametrically opposite pair, always retrograde in reckoning. |
| Sunrise | True rise-transit for your exact latitude and longitude — never a fixed 6 a.m. This matters: the vāra, the horā, the tribhāga and the daylight eighths all descend from it. |
| Day reckoning | Sunrise to sunrise. A pre-dawn birth belongs to the previous vāra, and Horā applies that consistently in Ṣaḍbala as well as in the pañcāṅga. |
| Timezone | The UTC offset actually in force at the birth moment — DST and historical zone changes included. For births before standard time was adopted, Horā offers true Local Mean Time from the longitude, and defaults to it for pre-1900 births. |
| Vargas | All sixteen ṣoḍaśavarga divisions, D1 through D60, each computed from the exact longitude rather than from the rounded sign. |
| Places | A gazetteer of about 37,000 places shipped inside Horā — every Indian town of any size and every district and taluk headquarters — carrying historical names beside current ones, so a birth registered in Bombay, Madras or Trivandrum still finds Mumbai, Chennai and Thiruvananthapuram. Data from GeoNames, used under CC BY 4.0. It is bundled rather than fetched: a birthplace is the one input everything else depends on, and it must not stop working because a third party is unreachable. |
Seven astronomical anchor tests run against this layer on every change to the code. If a planet moves where it should not, the build is supposed to fail before anyone sees a chart.
Phala — the classical rules
Every interpretive statement descends from a digitised rule, and the rule carries its source. The texts Horā draws on:
- Bṛhat Parāśara Horā Śāstra — the foundation: house-lord effects for all twelve lords across all twelve bhāvas, yogas, daśā doctrine, avasthās.
- Phaladīpikā — the systematisation of planetary and house effects.
- Sārāvalī — particularly on yogas and planetary combinations.
- Jātaka Pārijāta — the extended tradition of interpretation.
- Muhūrta Cintāmaṇi — the tārā and candra bala tables and the election rules.
- Bṛhat Saṁhitā — the mundane indicators.
- Tājika Nīlakaṇṭhī — the annual (Varṣaphala) system.
- Rudrayāmala Tantra — the Yoginī daśā attribution.
A rule that cannot be sourced does not ship. Where a computation involves a modern simplification — and a few necessarily do — that simplification is disclosed inside the reading’s own basis line, not buried here.
The consensus layer
Fifteen readings of the chart are made independently: house lordships, functional benefic and malefic status derived from lordship, Ṣaḍbala, aṣṭakavarga, the divisional charts, yogas, graha and rāśi dṛṣṭi, argala, Jaimini chara kārakas and kārakāṁśa, avasthās, upagrahas, and the three daśā systems.
Their conclusions are combined into a weighted consensus across fourteen life domains, with a confidence level attached. The weights are configuration, not scripture — they are versioned as a named ruleset so that a reading can always be reproduced against the exact rules that produced it.
Contradictions are surfaced, not resolved by fiat. When two readings point in opposite directions with real support on both sides, Horā reports the conflict. A chart that genuinely contains tension should read as tense.
Where traditions differ
Jyotiṣa is not one uniform system, and pretending otherwise is a form of dishonesty. Where practitioners legitimately disagree — the reference point for Manglik, the dual-lord convention in Chara daśā, the reckoning of Gulika, the pañcādhikārī ladder for the year lord — Horā picks a defensible convention and says which one it picked, in the basis line of the very statement that depends on it.
What Horā deliberately refuses
- No invented verses, ever. A citation points at a real passage.
- No language model anywhere in the prediction path.
- No point predictions about lifespan; āyur-yoga is presented as a framework only.
- No medical, psychological, financial or legal advice. See the disclaimer.
How to check us
Cast a chart you already know well and compare the planetary longitudes against any professional source. Then open any statement in the reading and follow its citation into the text. Both should hold. If either does not, tell us — source corrections are the most useful message this project receives.
See it on your own chart.
Free, no account, every claim sourced.
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