Installation

Requirements

Python 3.10 or higher
pip (Python package installer)

Install from PyPI

The easiest way to install ndastro-engine is from PyPI:

pip install ndastro-engine

Install for Development

If you want to contribute or modify the package:

Clone the repository:

git clone https://github.com/jaganathanb/ndastro-core.git
cd ndastro-core

Create a virtual environment (recommended):

python -m venv venv
source venv/bin/activate  # On Windows: venv\Scripts\activate

Install in development mode with dev dependencies:
```
pip install -e ".[dev]"
```

Verify Installation

To verify the installation works correctly:

import ndastro_engine
from datetime import datetime
from ndastro_engine.ayanamsa import get_lahiri_ayanamsa

# Calculate ayanamsa
date = datetime(2026, 1, 11, 12, 0, 0)
ayanamsa = get_lahiri_ayanamsa(date)
print(f"Lahiri Ayanamsa: {ayanamsa:.6f}°")

If this runs without errors, you're all set!

Dependencies

The package automatically installs these dependencies:

skyfield (>= 1.53): For astronomical calculations
pytz (>= 2025.2): For timezone handling

Optional Development Dependencies

For development, these additional packages are included:

pytest: Testing framework
pytest-cov: Code coverage
pytest-xdist: Parallel test execution
ruff: Linting and formatting
mypy: Static type checking

Troubleshooting

Import Errors

If you encounter import errors, ensure you're using Python 3.10 or higher:

python --version

Ephemeris Data

On first run, skyfield will automatically download JPL ephemeris data (~10MB). This is a one-time download and is cached locally.

Virtual Environment Issues

If you have issues with virtual environments, try recreating it:

deactivate  # if already in a venv
rm -rf venv  # or rmdir /s venv on Windows
python -m venv venv
source venv/bin/activate  # or venv\Scripts\activate on Windows
pip install ndastro-engine