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Swiss Ephemeris

Local
github.com/dm0lzGames & Entertainment10Updated 68w ago
Repository

About Swiss Ephemeris

Swiss Ephemeris is an MCP server for astronomical and astrological calculations based on the Swiss Ephemeris library. It serves users and agents that need planetary positions, chart data, transits, solar returns, or synastry for dates and locations.

Key features

  1. 01Planetary and asteroid positions
  2. 02Placidus 12-house calculations
  3. 03Chart points and lunar nodes
  4. 04Transit comparisons with natal charts
  5. 05Solar return and synastry charts

Use cases

  1. 01Calculating positions for a date and location
  2. 02Comparing natal charts with current transits
  3. 03Generating solar return charts for a year
  4. 04Comparing two birth charts

MCP support

Exposes four calculation tools to MCP clients: planetary positions, transits, solar revolution, and synastry. Supports STDIO and HTTP transports.

#swiss-ephemeris#astrology#ephemeris

Configuration

Local server config is the same for every client. Copy it into your client’s MCP config file.

mcp.json · Universal config
{
  "mcpServers": {
    "swiss-ephemeris": {
      "command": "docker",
      "args": [
        "run",
        "-i",
        "--rm",
        "olivier86/swiss-ephemeris-mcp-server:latest"
      ]
    }
  }
}
Run commanddocker run -i --rm olivier86/swiss-ephemeris-mcp-server:latest

Local servers need a runtime on your machine (e.g. Node.js 18+). Config file locations differ by client; see your client’s docs.

Packages
ociolivier86/swiss-ephemeris-mcp-server:latest

Tools

No tool list yet

Local servers expose tools only once running on your machine, and the maintainer has not provided a tool list.

Details

From the project README

Swiss Ephemeris MCP Server

A Model Context Protocol (MCP) server that provides astronomical calculations using the Swiss Ephemeris library. Calculate planetary positions, houses, chart points, and asteroids for any date and location.

Features

  • Planetary Positions: Sun, Moon, Mercury, Venus, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto
  • Lunar Nodes: True and Mean Node calculations
  • Asteroids: Chiron, Ceres, Pallas, Juno, Vesta, Lilith
  • Houses: 12-house system using Placidus
  • Chart Points: Ascendant, Midheaven, IC, Descendant
  • Additional Points: South Node, Part of Fortune

Installation

Prerequisites for Local Development

For local use with Claude Desktop, you need to install the Swiss Ephemeris swetest command:

# Install swetest (required for Claude Desktop usage)
git clone https://github.com/aloistr/swisseph.git /tmp/swisseph && \
    cd /tmp/swisseph && \
    make && \
    cp swetest /usr/local/bin/ && \
    rm -rf /tmp/swisseph
Claude Desktop

Add to your Claude Desktop configuration:

{
  "mcpServers": {
    "swissEphemeris": {
      "command": "npx",
      "args": ["github:dm0lz/swiss-ephemeris-mcp-server"]
    }
  }
}
Manual Installation
git clone https://github.com/dm0lz/swiss-ephemeris-mcp-server.git
cd swiss-ephemeris-mcp-server
npm install
npm start

Usage

The server provides four main tools:

calculate_planetary_positions

Calculate astronomical data for a specific date, time, and location.

Parameters:

  • datetime (string): ISO8601 format, e.g., "1985-04-12T23:20:50Z"
  • latitude (number): Latitude in decimal degrees (-90 to 90)
  • longitude (number): Longitude in decimal degrees (-180 to 180)

Returns:

  • planets: Positions of all planets and celestial bodies
  • houses: 12 astrological houses
  • chart_points: Ascendant, Midheaven, IC, Descendant
  • additional_points: South Node, Part of Fortune
calculate_transits

Calculate birth chart positions and current transits for comparison.

Parameters:

  • birth_datetime (string): Birth datetime in ISO8601 format
  • latitude (number): Birth latitude in decimal degrees
  • longitude (number): Birth longitude in decimal degrees

Returns:

  • natal_chart: Complete birth chart data
  • current_transits: Current planetary positions
  • calculation_time: Timestamp of transit calculation
calculate_solar_revolution

Calculate solar return chart for a specific year (when Sun returns to natal position).

Parameters:

  • birth_datetime (string): Birth datetime in ISO8601 format
  • birth_latitude (number): Birth latitude in decimal degrees
  • birth_longitude (number): Birth longitude in decimal degrees
  • return_year (number): Year for solar return calculation (e.g., 2024)
  • return_latitude (number, optional): Solar return location latitude
  • return_longitude (number, optional): Solar return location longitude

Returns:

  • natal_chart: Original birth chart data
  • solar_return_chart: Solar return chart for the specified year
  • natal_sun_longitude: Original Sun position in degrees
  • return_sun_longitude: Solar return Sun position in degrees
  • calculation_time: Timestamp of calculation
calculate_synastry

Calculate synastry chart between two people for relationship compatibility analysis.

Parameters:

  • person1_datetime (string): Person 1 birth datetime in ISO8601 format
  • person1_latitude (number): Person 1 birth latitude in decimal degrees
  • person1_longitude (number): Person 1 birth longitude in decimal degrees
  • person2_datetime (string): Person 2 birth datetime in ISO8601 format
  • person2_latitude (number): Person 2 birth latitude in decimal degrees
  • person2_longitude (number): Person 2 birth longitude in decimal degrees

Returns:

  • person1_chart: Complete birth chart for person 1
  • person2_chart: Complete birth chart for person 2
  • synastry_aspects: Array of planetary aspects between the charts
  • calculation_time: Timestamp of calculation

Docker

# Build and run
docker build -t swiss-ephemeris-mcp .
docker run -p 8000:8000 -e MCP_HTTP_MODE=true swiss-ephemeris-mcp

# Health check
curl http://localhost:8000/health

Transport Modes

  • Stdio: Default mode for Claude Desktop integration
  • HTTP: Use MCP_HTTP_MODE=true for web integration via ngrok

Links

License

MIT

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