Ascendant

Ascendant is a Python library for Vedic Astrology calculations, providing functionalities for charts, dashas, and yogas.

Installation

Install via pip:

pip install astro-ascendant

Ascendant calculates sidereal positions directly with the bundled pyswisseph dependency; no flatlib installation is required.

Documentation

The documentation is a separate Fumadocs app in docs/, backed by Markdown files in docs/content/.

cd docs
bun install
bun run dev

Open http://localhost:3000/docs, or browse the source pages directly:

• Divisional Charts (Vargas)
• Dasha Systems
• Yoga Combinations

The docs app is independent: create or configure its Vercel project with docs/ as the project root.

Codex and Agent Skills

This repository is also the canonical source for the Ascendant agent skills. The plugin bundle lives under plugins/agent/, and the same plugins/{scope}/skills layout is discoverable by the skills CLI.

Install the skills with:

npx skills add thaletto/ascendant

Add the Codex marketplace from Git and install the plugin with:

codex plugin marketplace add https://github.com/thaletto/ascendant.git --ref main
codex plugin add agent@ascendant

Core Functionalities:

• Chart Calculations: Compute and analyze divisional astrological charts (Varga chakras).
• Dasha System: Implementation of the Vimshottari Dasha system for planetary periods.
• Yoga Combinations: Identification and interpretation of various Yoga (planetary combinations).
• Ashtakavarga: Classical Bhinnashtakavarga, Sarvashtakavarga, Shodhana, and Shodhya Pinda calculations.

Usage

from ascendant import Ascendant

# Initialize with birth details
astro = Ascendant(
    year=1990, month=1, day=1,
    hour=12, minute=0, second=0,
    latitude=28.6139, longitude=77.2090,
    utc="+5:30"
)

# Get Rasi Chart (D1)
chart = astro.get_chart(division=1)

# Get Yogas
yogas = astro.get_yogas()

# Get Dasha Timeline
dasha = astro.get_dasha_timeline()

# Get Ashtakavarga / Sarvashtakavarga
ashtakavarga = astro.get_sav()
sarva = ashtakavarga["sarva"]

Advanced Usage

Override the built-in Lahiri and Whole Sign defaults for one chart:

astro = Ascendant(
    ...,
    ayanamsa="Krishnamurti",
    house_system="Equal",
)

Configure typed application-wide defaults once when most charts use the same calculation settings:

from ascendant import (
    AscendantConfig,
    Ayanamsa,
    HouseSystem,
    configure,
)

configure(
    AscendantConfig(
        ayanamsa=Ayanamsa.LAHIRI,
        house_system=HouseSystem.PORPHYRY,
    )
)

astro = Ascendant(...)  # Uses Lahiri and Porphyry.

Explicit Ascendant arguments take precedence over the configured defaults. Configuration is immutable and is captured when each instance is created. Use get_config() to inspect the current defaults and reset_config() to restore Lahiri and Whole Sign. Unsupported constructor values raise ValueError.

Available Ayanamsa

• Lahiri (default)
• Lahiri_1940
• Lahiri_VP285
• Lahiri_ICRC
• Raman
• Krishnamurti
• Krishnamurti_Senthilathiban

Available House System

• Whole Sign (default)
• Placidus
• Equal
• Equal 2
• Porphyry

Accuracy Verification

Run the Swiss Ephemeris reference cases independently:

.venv/bin/python -m pytest tests/test_swiss_ephemeris_accuracy.py -vv

The cases compare sidereal Sun, Moon, ascendant, and house cusp positions against fixed reference values with a maximum angular error of 0.1°. They cover Whole Sign, Placidus, Equal, and Porphyry house systems across multiple ayanamsas and dates. The Porphyry case also checks House 2 so the test distinguishes its cusps from systems that share the same ascendant and first house cusp.