Open Ephemeris gives ChatGPT real astronomy to work from. Every position comes from the NASA JPL DE440 ephemeris covering 1550-2650 CE at sub-arcsecond precision, the same kernel used for spacecraft navigation, so positions are computed rather than estimated.
Ask for a natal chart and an interactive wheel opens in the conversation. Click a planet, a house, or an aspect line and the interpretation loads in place. Switch house systems without asking again. The same applies to Human Design bodygraphs, synastry bi-wheels, transit timelines, Vedic Rashi grids and BaZi Four Pillars charts.
Beyond charts: transits and progressions, solar and lunar returns, eclipse timing and local visibility, astrocartography, electional search for timing windows, and fixed-star positions.
Free to start, no card required.
How to use
- 1Add it in ChatGPT
Open Open Ephemeris in ChatGPT's Plugin directory (button above), select + to add it and sign in if asked.
- 2Use it in a chat
Type @ in the composer and pick Open Ephemeris, or start your message with its name. ChatGPT may also suggest it when it fits what you ask.
Things to ask
- “Make me an interactive natal chart for July 20, 1969 at 8:17 PM in Houston, Texas.”
- “Show me the Human Design bodygraph for someone born January 15, 1990 at 10:00 AM in London.”
- “What's the moon phase right now, and when is the next full moon?”
Disconnect
- 1Disconnect it in ChatGPT
Open Settings, then Apps or Plugins (the label depends on your rollout), select Open Ephemeris and choose Disconnect. ChatGPT stops acting through your account; past conversations aren't deleted.