Prasna (Vedic Horary Astrology)¶

Prasna Shastra is the classical Vedic system of predicting what a person came to ask about before they speak. At the exact moment of arrival, the Lagna (ascendant), Moon, 7th lord, and dominant planet collectively encode the nature of the unspoken query.

The prasna service applies six classical rules to score all 12 houses of the chart, then returns the top-3 predicted topics, each with a full analytical paragraph.

The public result dataclasses live in ndastro_api.core.models.prasna.

API Endpoint¶

Method	Path	Summary
`GET`	`/api/v1/prasna/query-topic`	Predict the topic of an unspoken query from the current chart

`GET /api/v1/prasna/query-topic`¶

Query Parameters¶

Parameter	Type	Required	Description
`lat`	`float`	✓	Geographic latitude of the questioner
`lon`	`float`	✓	Geographic longitude of the questioner
`dateandtime`	`string`	—	ISO 8601 datetime of the query (defaults to current UTC)
`ayanamsa`	`string`	—	Ayanamsa system (default `lahiri`)

Response Shape¶

{
  "datetime_utc": "2026-07-19T08:30:00+00:00",
  "chart": { ...PrasnaChartSnapshot... },
  "topics": [ ...PrasnaTopicResult × 3... ],
  "disclaimer": "Prasna Shastra is an indicative classical system..."
}

`PrasnaChartSnapshot` Fields¶

Field	Type	Description
`lagna_sign_number`	`int`	Ascending sign 1–12 at query time
`lagna_sign_name`	`string`	e.g. `Leo`
`lagna_lord_code`	`string`	Planet code of the Lagna lord (e.g. `SU`)
`lagna_lord_house`	`int`	House (1–12) where the Lagna lord is placed
`moon_sign_number`	`int`	Moon's sign 1–12
`moon_sign_name`	`string`	e.g. `Aquarius`
`moon_house`	`int`	Moon's whole-sign house (1–12)
`moon_nakshatra_number`	`int`	Nakshatra 1–27
`moon_nakshatra_name`	`string`	e.g. `Shatabhisha`
`moon_nakshatra_lord_code`	`string`	Lord of Moon's nakshatra
`seventh_lord_code`	`string`	Planet code of the 7th house lord
`seventh_lord_house`	`int`	House where 7th lord is placed
`strongest_planet_code`	`string`	Most dignified planet in the chart
`strongest_planet_house`	`int`	House where the strongest planet sits
`strongest_planet_sign_name`	`string`	Sign of the strongest planet

`PrasnaTopicResult` Fields¶

Field	Type	Description
`rank`	`int`	1 = most likely, 3 = third most likely
`topic`	`string`	Short label, e.g. `"Marriage & Partnership"`
`confidence`	`float`	Normalised score 0.0–1.0
`primary_house`	`int`	House (1–12) that drives this prediction
`primary_indicator`	`string`	One-sentence classical rule trigger
`paragraph`	`string`	Full Prasna analysis with reasoning

The Six Classical Prasna Rules¶

The service scores each house (1–12) by applying the following rules in order of weight:

#	Rule	Weight	Classical Basis
1	Moon's house	3.0	Moon = mind; the house it occupies shows the questioner's preoccupation
2	7th lord's house	2.0	The 7th represents "what you came about" — the object of the query
3	Lagna lord's house	2.0	The Lagna lord reflects the self and its primary concern
4	Strongest planet's house	1.5	The most dignified planet activates its house's significations
5	Most occupied house	0.7/planet	Where planets cluster, energy focuses
6	Moon's nakshatra lord's house	1.0	Fine-grained nakshatra-level indicator

Additionally, planets in Kendra houses (1, 4, 7, 10) add a small boost (0.3 per planet) to those houses.

All house scores are normalised to 0–1 before ranking. The top-3 houses become the topic predictions.

House → Topic Mapping¶

House	Short Label	Typical Query Subject
1	Health & Self	Your health, body, appearance, or a deeply personal matter
2	Wealth & Family	Money, savings, pending income, family finances, or an asset
3	Communication & Siblings	A sibling, short journey, agreement, document, or decision requiring courage
4	Home, Property & Mother	Land, a house, a vehicle, your mother, or an educational institution
5	Children & Creativity	A child, romantic relationship, creative project, or investment
6	Enemies, Debt & Disease	A health problem, a debt, an enemy, or a legal dispute
7	Marriage & Partnership	A spouse, business partner, or significant agreement with another
8	Crisis, Secrets & Transformation	An inheritance, sudden event, hidden matter, or major life change
9	Fortune, Dharma & Long Journeys	Luck, religion, a long journey, your father, or guidance on the right path
10	Career & Status	Your career, a job matter, a promotion, or dealings with authority
11	Gains & Desires	Pending income, a fulfilled wish, or a friendship/network matter
12	Loss, Foreign & Spiritual	An expense, a loss, foreign travel, hospitalisation, or a spiritual question

Planet Dignity — Strength Calculation¶

The strongest planet is identified using classical dignity scores:

Placement	Score
Exaltation sign	3.0
Own sign	2.5
Friendly sign	2.0
Neutral sign	1.5
Enemy sign	0.8
Debilitation sign	0.25

Exaltation / Debilitation signs:

Planet	Exaltation	Debilitation
Sun	Aries	Libra
Moon	Taurus	Scorpio
Mars	Capricorn	Cancer
Mercury	Virgo	Pisces
Jupiter	Cancer	Capricorn
Venus	Pisces	Virgo
Saturn	Libra	Aries

Result Models (`ndastro_api.core.models.prasna`)¶

`PrasnaResult`¶

Top-level return type from analyse_prasna_query.

Field	Type	Description
`datetime_utc`	`str`	ISO 8601 UTC datetime of the query
`chart`	`PrasnaChartSnapshot`	Key chart elements
`topics`	`tuple[PrasnaTopicResult, ...]`	3 ranked predictions

`PrasnaChartSnapshot`¶

Immutable snapshot of the key indicators — see chart fields above.

`PrasnaTopicResult`¶

One ranked prediction — see topic fields above.

Service Function¶

from ndastro_api.services.prasna import analyse_prasna_query

result = analyse_prasna_query(
    lat=12.971667,
    lon=77.593611,
    dt=datetime.now(timezone.utc),
    ayanamsa_system="lahiri",   # default
)

Returns a PrasnaResult. The function uses get_planet_position and get_ascendent_position from ndastro_engine and applies whole-sign houses throughout.

Usage Example¶

GET /api/v1/prasna/query-topic?lat=12.971667&lon=77.593611

Typical response (abridged):

{
  "datetime_utc": "2026-07-19T08:30:00+00:00",
  "chart": {
    "lagna_sign_name": "Leo",
    "lagna_lord_code": "SU",
    "lagna_lord_house": 1,
    "moon_sign_name": "Aquarius",
    "moon_house": 7,
    "moon_nakshatra_name": "Shatabhisha",
    "moon_nakshatra_lord_code": "RA",
    "seventh_lord_code": "SA",
    "seventh_lord_house": 7,
    "strongest_planet_code": "JU",
    "strongest_planet_house": 5,
    "strongest_planet_sign_name": "Sagittarius"
  },
  "topics": [
    {
      "rank": 1,
      "topic": "Marriage & Partnership",
      "confidence": 0.82,
      "primary_house": 7,
      "primary_indicator": "Moon occupies the 7th house",
      "paragraph": "At the moment of this query, Leo rises as the Lagna with Sun as its lord, now placed in the 1st house. The Moon — representing the mind and its preoccupations — occupies Aquarius in the 7th house, within the nakshatra Shatabhisha whose lord is Rahu. Classically, the 7th lord (Saturn) reveals what the questioner came about; here it resides in the 7th house. The strongest planet in this chart is Jupiter in Sagittarius (the 5th house). The dominant Prasna indicator here is: Moon occupies the 7th house. Taken together, these classical signs point with strong conviction toward a relationship — marriage, a business partner, or an agreement with another person. You appear to have come with a question about another person — a spouse, a life partner, a business associate, or a significant agreement or negotiation involving someone else."
    },
    ...
  ],
  "disclaimer": "Prasna Shastra is an indicative classical system..."
}

Disclaimer

Prasna Shastra predictions are based on classical house-scoring rules applied at the moment of query. They are indicative, not definitive. Always interpret results in the context of the full chart and with guidance from a qualified Vedic astrologer.

Surprise Effect

The endpoint is designed so that the API caller can show the rank-1 topic to the questioner before the questioner has stated their concern — the classical Prasna astrologer's signature move. The paragraph field explains the full reasoning chain so the caller can narrate it naturally.

Prasna (Vedic Horary Astrology)¶

API Endpoint¶

GET /api/v1/prasna/query-topic¶

Query Parameters¶

Response Shape¶

PrasnaChartSnapshot Fields¶

PrasnaTopicResult Fields¶