openephemeris

Compute high-precision planetary positions using NASA JPL DE440 ephemeris data.

3|Updated Mar 19, 2026

Search Tags:#mcp #astrology #astronomy #natal-chart #ephemeris #human-design

Ready to run

npx skills add https://github.com/openephemeris/openephemeris-MCP --skill openephemeris

💬 Prompt for ChatGPT / Claude Chat▼

Please help me install this Agent Skill.
Skill: openephemeris
Source: https://github.com/openephemeris/openephemeris-MCP/tree/main/plugin/openephemeris
Command: npx skills add https://github.com/openephemeris/openephemeris-MCP --skill openephemeris

SYSTEM DOCUMENTATION & REQUIREMENTS

💡 This Skill includes assets (resource) components.

What problem does it solve?

This skill eliminates the guesswork and manual calculation errors in astrological and astronomical research by providing high-precision, NASA-grade planetary data directly within your conversation.

Core Features & Use Cases

High-Precision Computation: Access natal charts, transits, synastry, and Human Design bodygraphs using the JPL DE440 ephemeris.
Predictive Timing: Scan date ranges for optimal electional windows or track planetary returns and eclipses.
Use Case: A user can ask for a natal chart analysis for a specific birth time and location, receiving accurate house cusps, aspects, and essential dignities without needing to consult external software.

Quick Start

Ask the openephemeris skill to calculate a natal chart for a person born on April 15 1990 at 2:30 PM in Chicago.

Frequently Asked Questions about openephemeris

High-intent search queries and answers about installing and using this skill.

FAQPage Schema

How do I calculate a natal chart with high-precision planetary positions?▼

Natal chart generation requires providing a specific birth date, time, and location to receive accurate house cusps, aspects, and essential dignities using the JPL DE440 ephemeris data.

What is the JPL DE440 ephemeris used for in astrology calculations?▼

The JPL DE440 ephemeris provides NASA-grade astronomical data for astrology calculations, enabling sub-arcsecond planetary position accuracy for transit analysis, electional timing, and synastry without manual computation errors.

Can I generate a Human Design bodygraph using birth data?▼

Yes, you can generate a Human Design bodygraph by supplying valid birth data, which processes sub-arcsecond planetary positions to construct the bodygraph accurately within the conversation.

How do I find optimal electional timing windows by scanning date ranges?▼

Finding optimal electional timing involves scanning specified date ranges to track planetary returns and eclipses, identifying favorable windows using high-precision astronomical calculations from the ephemeris data.

Do I need API authentication to perform astronomical computations?▼

Yes, valid API authentication is required to perform sub-arcsecond planetary position calculations and house cusp determinations for complex astronomical and astrological research tasks.

What are the limitations of using ephemeris data for transit analysis?▼

Ephemeris data limitations for transit analysis depend on the precision of the input birth time and location, as sub-arcsecond calculations require accurate timestamps to avoid skewed house cusp determinations.