Skip to content

vedic-calc

Open-source Vedic astrology calculation library built on the Swiss Ephemeris.

vedic-calc provides accurate astronomical calculations for Vedic (sidereal) astrology -- planetary positions, birth charts, nakshatras, divisional charts, dasha periods, panchanga, compatibility, muhurta, prashna, and more -- with a clean, type-safe Python API.

Why vedic-calc?

Feature vedic-calc PyJHora pyswisseph (raw)
License AGPL-3.0 AGPL-3.0 Modified BSD
GUI dependencies None Requires PyQt6 None
API design Pydantic models, pure functions GUI-coupled, global state Low-level C bindings
Vedic astrology Built-in (14 modules) Built-in DIY
JSON serializable Yes (all models) No No

Features

Chart Calculation

  • Birth chart -- planetary positions, houses (Whole Sign), nakshatras, padas
  • Divisional charts -- D-1 through D-60 (Rasi, Navamsa, Dashamsa, and all standard vargas)
  • Aspects -- Vedic drishti (sign-based aspects with special aspects for Mars, Jupiter, Saturn)
  • Combustion -- proximity-based combustion detection with planet-specific orbs
  • Planetary states -- dignity (own sign, exaltation, debilitation, moolatrikona, friend/enemy), retrograde, dispositor chains
  • House analysis -- lord placement, occupants, aspecting planets, strength assessment
  • Transits -- current sky positions overlaid on natal chart
  • Special lagnas -- Hora Lagna, Ghati Lagna, Bhava Lagna, Sree Lagna
  • Upagrahas -- Dhuma, Vyatipata, Parivesha, Chapa, Upaketu
  • Sahams -- 21 Arabic parts (Punya Saham, Vidya Saham, etc.)
  • Rendering -- South Indian, North Indian (ASCII), and SVG chart diagrams

Planetary Periods

  • Vimsottari Dasha -- mahadasha, antardasha, pratyantardasha (120-year cycle)
  • Yogini Dasha -- 8 yogini deities (36-year cycle)
  • Ashtottari Dasha -- 8 planets excluding Ketu (108-year cycle)
  • Narayana Dasha -- Jaimini sign-based periods

Panchanga (Daily Calendar)

  • Five elements -- tithi, nakshatra, yoga, karana, vara
  • Sunrise/sunset for any location
  • Hindu festival detection

Yoga and Dosha Detection

  • Yogas -- ~20 classical yogas (Pancha Mahapurusha, Gajakesari, Dhana, Lakshmi, Budhaditya, Raja, Viparita Raja, Saraswati, Kemadruma, and more)
  • Doshas -- Mangal Dosha, Kaal Sarpa Dosha, Pitru Dosha, Grahan Dosha with severity levels and remedies

Strength Analysis

  • Shadbala -- six-fold planetary strength (positional, directional, temporal, motional, natural, aspectual)
  • Ashtakavarga -- 8-source benefic point system (per-planet and sarvashtakavarga)

Compatibility

  • Ashtakoot Milan -- North Indian 8-factor scoring (max 36 points) with Mangal Dosha check
  • Porutham -- South Indian 10-factor compatibility (Dina, Gana, Rajju, Vedha, etc.)

Muhurta (Electional Astrology)

  • Daily muhurta -- Rahu Kalam, Yamagandam, Gulika Kalam, Abhijit Muhurta, Choghadiya, Hora
  • Muhurta solver -- find auspicious windows for any activity within a date range, with 5-layer panchanga filtering and personal overlays (Chandrabala, Tarabala)

Prashna (Horary Astrology)

  • Prashna chart casting -- chart for the moment a question is asked
  • Tajika yogas -- degree-based aspect patterns (Ithasala, Easarapha, Induvara, Kamboola, Nakta)
  • Verdict engine -- favorable/unfavorable/mixed with reasoning

Jaimini System

  • Chara Karakas -- 7 variable significators based on planetary degrees
  • Arudha Padas -- image/projection of each house

Annual Predictions

  • Varshaphal -- solar return chart, Muntha (progressed ascendant), annual Tajika yogas

KP System (Krishnamurti Paddhati)

  • KP chart -- Placidus house cusps with sign lord, star lord, sub lord
  • Sublord lookup -- 249-division KP sublord table

Numerology

  • Chaldean system -- psychic number, destiny number, name number with interpretation

Quick Start

# Install
pip install vedic-calc

# Or with uv
uv add vedic-calc

from vedic_calc import calculate_chart

chart = calculate_chart(
    year=1990, month=3, day=15,
    hour=10, minute=30,
    latitude=19.0760, longitude=72.8777,  # Mumbai
    timezone_offset=5.5,                   # IST
)

# Access planetary positions
for planet, pos in chart.planets.items():
    print(f"{planet.name}: {pos.sign.name} {pos.degree_in_sign:.1f}")

# JSON export
print(chart.model_dump_json(indent=2))

Design Principles

  1. Accuracy first -- Swiss Ephemeris for positions, cross-validated against astronomical facts and PyJHora
  2. Pure functions -- no global state, no side effects, easy to test
  3. Immutable data -- all models are frozen Pydantic BaseModels
  4. Thin abstraction -- only ephemeris.py touches pyswisseph, everything else is pure Python
  5. Zero GUI dependencies -- headless library, not a desktop app