Explore Moira as an optional calculation backend or validation companion

[TheDaniel166]

Hi Kosmorro maintainers,

I wanted to share an idea for discussion: would there be interest in exploring Moira as an optional calculation backend or companion library for Kosmorro / Kosmorrolib?

Moira is a pure-Python ephemeris and astrology computation engine focused on transparent, auditable calculations, reproducibility, and an inspectable calculation chain from astronomical inputs to outputs. Since Kosmorro already provides a user-facing way to calculate ephemerides, I think there may be some interesting overlap worth exploring.

The idea would not be to replace Kosmorro’s current approach, but to investigate whether Moira could provide value in one or more of these ways:

Optional backend support
Add Moira as an experimental or optional backend for certain calculations, allowing comparisons against the current Skyfield-based pipeline.
Validation / cross-checking
Use Moira to independently verify selected ephemeris outputs, especially for regression testing or precision audits.
Transparent calculation traces
Expose more detailed intermediate calculation data for users who want to inspect how a result was produced.
Astrology-adjacent extensions kept separate from core astronomy
If Kosmorro wants to remain astronomy-first, Moira could still offer optional downstream tooling for users who want astrological chart calculations based on astronomical positions, without changing Kosmorro’s core identity.
Shared test fixtures / interoperability
Define a small compatibility layer or common output schema so both projects can compare results for dates, locations, planetary positions, Moon phases, and related events.

A possible first step could be a small proof of concept that compares Kosmorro/Kosmorrolib and Moira outputs for a few fixed dates and locations, then documents any differences in precision, dependencies, runtime, and API ergonomics.

I’d be happy to help with exploration, benchmarks, or a prototype if this sounds interesting.

Thanks for considering it!

[Deuchnord]

Hello Daniel,

I'm sorry, but I prefer Kosmorro to remain astronomy-first. I'm not in astrology at all, and adding this feature in my project would just contribute to the confusion for the general public between both activities.

Optional backend support
Add Moira as an experimental or optional backend for certain calculations, allowing comparisons against the current Skyfield-based pipeline.
Validation / cross-checking
Use Moira to independently verify selected ephemeris outputs, especially for regression testing or precision audits.

This validation step would add a lot of steps (and add much longer time) in Kosmorro for very few benefit. Plus, I would need to be very confident to your calculations. For information, the data I use in the tests to cross-check that the calculations are correct are taken from public websites like this application by Paris Observatory for ephemerides, and from other popular sources like Stellarium, Celestia or Wikipedia for events.

Expose more detailed intermediate calculation data for users who want to inspect how a result was produced.

Having more detailed logs would probably benefit for development, but Kosmorro is meant for amateur astronomers, I don't think they care how calculations are made, they just want them to be correct.

Astrology-adjacent extensions kept separate from core astronomy

There is already a project for an output plugin system: Kosmorro/kosmorro#427. When it'll be ready, you can just use it to create your own plugin to generate whatever output you want.

You can still use Kosmorrolib in your project as soon as you respect the license (notably: share modified source code, clearly say your app uses Kosmorrolib without implying I support your work).

P.-S. If you want to contribute to Kosmorro or Kosmorrolib, I do not accept LLM-generated code.