vedic-panchanga

A complete Vedic Panchanga and Kundali (birth chart) calculator for Node.js and browsers, written in TypeScript. Uses the Swiss Ephemeris via @swisseph/browser (WebAssembly) for astronomical calculations and pure TypeScript for all astrological logic.

Try the live interactive demo: https://reflexdemon.github.io/vpv-panchangam/

Features

• Full Drik Panchang: Tithi, Nakshatra, Yoga, Karana, Vara, Moon sign, Sun sign
• Auspicious timings: Brahma Muhurta, Abhijit, Vijay, Godhuli, Nishita, Amrit Kalam, Sarvartha/Amrita Siddhi Yoga
• Inauspicious timings: Rahu Kalam, Yamaganda, Gulika, Dur Muhurtam, Bhadra, Varjyam
• Gowri Panchangam (8+8 segments) and Planetary Hora (12+12)
• Nalla Neram (auspicious hours after subtracting inauspicious windows)
• Tyajyam: all 10 types (Nakshatra, Tithi, Vara, Amritadi, Lagna, Karana, Gowri, Dosha, Tithi-Lagna, Tamil Month)
• Calendars: Shaka, Vikram, Kali, Gujarati, National Civil, Nirayana solar, Lunar month
• Ritu/Ayana, Chandra Vasa, Disha Shool, Rahu Vasa
• Birth Chart (Kundali): All 17 divisional charts (D1–D60), including D11 Rudramsa
• Vimshottari Dasha: Mahadasha + Antardasha + Pratyantar
• Ashtakavarga: BAV + SAV for all 7 planets
• Special placements: Exaltation, debilitation, own sign, Moolatrikona, Vargottama, Digbala, Pushkara, Mrityu Bhaga, Gandanta, Neecha Bhanga, Parivartana, Graha Yuddha
• Jaimini Chara Karakas + Karakamsa/Swamsa
• Planetary friendships (natural, temporal, composite)
• Graha Drishti (aspects with strength)
• Kalsarpa Yoga detection
• Locales: English (en), Hindi/Devanagari (hi), Tamil (ta)

Requirements

• Node.js 20+ (Node only; browsers are also supported)

Installation

npm install vedic-panchanga

The astronomical engine ships as a WebAssembly module inside @swisseph/browser; no native C++ build step is required. In browsers the engine is loaded automatically; in Node.js a small fetch shim is installed on first use to serve the bundled .wasm.

Browser usage

The package is compiled to CommonJS with a dynamic import() of the ESM-only @swisseph/browser package, so it also works in bundlers that support dynamic imports (Vite, webpack, Rollup …). WASM loading follows the standard @swisseph/browser path — no extra configuration needed.

Quick Start

Panchang (Daily Almanac)

import { computeDetailedPanchang } from 'vedic-panchanga';

const panchang = await computeDetailedPanchang(
  '2026-07-04',       // date (YYYY-MM-DD), defaults to today
  34.075,             // latitude
  -84.294,            // longitude
  'America/New_York', // IANA timezone (defaults to 'UTC')
  'en',               // locale: 'en' | 'hi' | 'ta'
);

console.log(panchang.vara.english);           // "Saturday"
console.log(panchang.panchang.tithi?.name);   // e.g. "Ashtami"
console.log(panchang.sun_moon.sunrise);       // ISO datetime string
console.log(panchang.auspicious_timings.abhijit);
// { start: "2026-07-04T17:23:00.000Z", end: "2026-07-04T18:11:00.000Z" }

Birth Chart (Kundali)

import { computeChart } from 'vedic-panchanga';

const chart = await computeChart(
  {
    date:      '1990-03-15',
    time:      '08:30',          // 24-hour local time
    latitude:  28.6139,
    longitude: 77.2090,
    timezone:  'Asia/Kolkata',
    ayanamsa:  'lahiri',         // default
  },
  'en',  // locale
);

console.log(chart.ascendant.sign);             // "Aries"
console.log(chart.planets_data[0].name);       // "Sun"
console.log(chart.dasha[0].lord);              // Current Mahadasha lord
console.log(chart.d9_chart.asc_sign);          // D9 ascendant sign id (1-12)
console.log(chart.kalsarpa.present);           // true/false
console.log(chart.ashtakavarga.sav);           // [12 SAV totals per sign]

Hindi / Tamil output

const panchang = await computeDetailedPanchang(
  '2026-07-04', 13.083, 80.270, 'Asia/Kolkata', 'ta'
);
console.log(panchang.vara.sanskrit);           // "சனிவாரம்"
console.log(panchang.panchang.nakshatra?.name); // Tamil nakshatra name

API Reference

computeDetailedPanchang(date?, latitude, longitude, timezone?, locale?)

Returns a Promise<PanchangResponse>. All time strings are UTC ISO-8601.

| Parameter | Type | Default | Description | |-------------|----------|-------------|-------------------------------------| | date | string | today | YYYY-MM-DD | | latitude | number | 0 | Geographic latitude (−90 to 90) | | longitude | number | 0 | Geographic longitude (−180 to 180) | | timezone | string | 'UTC' | IANA timezone identifier | | locale | Locale | 'en' | 'en', 'hi', or 'ta' |

Throws PanchangError with codes: INVALID_DATE, INVALID_LOCATION, CALCULATION_FAILED, EPHEMERIS_ERROR.

computeChart(birthInfo, locale?)

Returns a Promise<ChartResponse>.

interface BirthInfo {
  date:       string;      // YYYY-MM-DD
  time:       string;      // HH:MM (24-hour, local time)
  latitude:   number;
  longitude:  number;
  timezone?:  string;      // IANA, defaults to 'UTC'
  ayanamsa?:  AyanamsaId;  // defaults to 'lahiri'
}

Supported ayanamsas: lahiri, kp_new, kp_old, raman, kp_khullar, sayan, manoj

Throws ChartError with codes: INVALID_BIRTH_INFO, CALCULATION_FAILED, EPHEMERIS_ERROR.

Configuration

Ephemeris engine

The engine is @swisseph/browser (WebAssembly). init() is async and should be awaited once before calling the calculation functions (the public compute* functions auto-initialize):

import { EphemerisService } from 'vedic-panchanga';

const ephe = EphemerisService.getInstance();
await ephe.init({ ayanamsa: 'lahiri' }); // default

If you never call init() yourself, computeDetailedPanchang() / computeChart() initialize the engine (with the default lahiri ayanamsa) on first use.

Timezone

Unlike the Python backend, this library has no built-in coordinate-to-timezone lookup. Pass the IANA timezone string explicitly. If you need automatic resolution, use a package like geo-tz:

import { find } from 'geo-tz';
const [timezone] = find(lat, lon);

Locale system

All three locales are bundled and resolved at runtime:

import { getLocaleTable, resolveName } from 'vedic-panchanga';

const table = getLocaleTable('ta');
console.log(table.nakshatras[0]); // "அஸ்வினி"

const name = resolveName(0, 'nakshatras', 'hi');
console.log(name); // "अश्विनी"

Architecture

src/
├── index.ts               # Public barrel export
├── types.ts               # All TypeScript interfaces + error classes
├── locales/               # en, hi, ta locale tables
├── constants/             # Lookup tables (BAV rules, dashas, muhurta tables, etc.)
├── ephemeris/             # Swiss Ephemeris adapter (@swisseph/browser WASM wrapper)
├── calculations/          # Pure calculation modules
│   ├── bisection.ts       # Angular boundary search engine
│   ├── panchang.ts        # Tithi/nakshatra/yoga/karana index + sequence generators
│   ├── sunrise.ts         # Rise/set times + Udaya Lagna
│   ├── muhurta.ts         # Auspicious/inauspicious timing windows
│   ├── vargas.ts          # D1–D60 divisional charts
│   ├── dasha.ts           # Vimshottari dasha
│   ├── ashtakavarga.ts    # BAV + SAV
│   ├── placements.ts      # Special planetary placements
│   ├── jaimini.ts         # Chara karakas
│   ├── relationships.ts   # Planetary friendships
│   ├── aspects.ts         # Graha drishti
│   ├── kalsarpa.ts        # Kalsarpa yoga
│   ├── gowri.ts           # Gowri Panchangam
│   ├── hora.ts            # Planetary hora
│   ├── nalla-neram.ts     # Nalla Neram
│   ├── calendars.ts       # Multi-calendar conversions
│   ├── tyajyam/           # 10 tyajyam types
│   └── ganda-mula-ravi-yoga.ts
└── api/
    ├── get-panchang.ts    # computeDetailedPanchang() orchestration
    └── calculate.ts       # computeChart() orchestration

Development

npm run build        # Compile TypeScript → dist/
npm test             # Run Vitest test suite
npm run lint         # ESLint
npm run format       # Prettier
npm run test:watch   # Watch mode

License

MIT, aside from the bundled Swiss Ephemeris. @swisseph/browser (and the Swiss Ephemeris swisseph.wasm sidecar) is distributed under the AGPL-3.0 license by Astrodienst. If you use this package in a server or network service, the Swiss Ephemeris AGPL terms may apply to your distribution.