# Sources, independence, and licenses

The adapter, tests, UI helper, and original documentation are MIT. No Horosa or Swiss Ephemeris executable implementation, code fragment, algorithm translation, modern interpretive prose, or no-license writing is bundled. Numerical validation used the separate pyswisseph 2.10.3.2 test oracle; it is not distributed in the website. The mathematical implementations use geometric vector operations and the existing MIT Astronomy Engine 2.1.19 through its public API.

The profile names, standard integer identifiers, epoch dates/time scales, angular constants, and target star/plane definitions are interoperability facts. They have been organized into independently authored metadata. Reading the reference software was necessary to distinguish otherwise misleading names, including the full-plane epoch modes. It is not a claim to have implemented the historically disputed doctrines behind every name. The 47 numerical conventions are reproducible software definitions; historical provenance and numerical parity are separate questions.

## Sources

- Horosa reference enumeration and backend behavior: [Horosa](https://github.com/Horace-Maxwell/Horosa-Web-App-comprehensively-improved-Windows), pinned local audit commit `daab60ce05c8f0e78cc51b5e7974120f81aed79c`; `AstroConst.js`, `india_chart_kernel.py`, `perchart.py`, and `flatlib-ctrad2/flatlib/ephem/swe.py`. AGPL reference only, not copied or shipped. The repository URL is an upstream reference, not a claim that this prototype is affiliated with Horosa.
- [Swiss Ephemeris general documentation](https://www.astro.com/swisseph/swisseph.htm), sections 2.8 and Appendix E, checked 2026-10-02. Primary documentation of the software conventions, not a license to copy prose. All descriptions here are new.
- [Swiss Ephemeris programming interface](https://www.astro.com/swisseph/swephprg.htm), section 12, checked 2026-10-02. Distinguishes TT custom epochs, mean vs true offsets, full-plane projections, and default flag behavior.
- [Swiss Ephemeris mathematical definition constants](https://github.com/aloistr/swisseph/blob/master/sweph.h), version marker 2.10.03 inspected 2026-10-02. Used only to verify numerical epoch facts, time scales and the historical correction-model names. It is not a runtime dependency. [The official implementation](https://github.com/aloistr/swisseph/blob/master/sweph.c) was read to establish that J2000/J1900/B1950/Mardyks force epoch-plane projection and that Sheoran uses a Pushya target of 103.49264221625°. No implementation statements are copied into the adapter.
- [Astronomy Engine public JavaScript API](https://github.com/cosinekitty/astronomy/blob/master/source/js/README.md), MIT, copyright Don Cross. Existing workbench vendor `astronomy.js` carries its full license. Calls used: TT/UT conversion, ecliptic rotations, obliquity/nutation, Earth barycentric state. Its truncated nutation has a documented roughly two-arcsecond design accuracy. The adapter does not claim additional precision merely because it prints more decimals.
- [HYG v4.1](https://github.com/astronexus/HYG-Database/blob/c7f7f883fe678cc7680169a50ccd7dcc49b060ce/hyg/CURRENT/hygdata_v41.csv), David Nash / Astronomy Nexus and contributors, CC BY-SA 4.0. Four records selected from the existing authorized local catalogue: HIP 65474 Spica, 5737 Revati, 42911 Pushya, 85927 Shaula/Mula. The derived `sidereal-star-data.json` and `.js` remain [CC BY-SA 4.0](https://creativecommons.org/licenses/by-sa/4.0/). Selection and numeric conversion are described in each file. This dataset's license is separate from the MIT code.
- [Liu, Zhu, Zhang, Reconsidering the Galactic coordinate system](https://arxiv.org/pdf/1010.3773), equations 19 and 22. The two pole directions are mathematical facts from the original paper. The IAU1958-derived ICRS pole and the proposed newer pole are kept distinct. The latter is not described as a newly adopted IAU standard.
- [Reid & Brunthaler 2004, The Proper Motion of Sagittarius A*](https://arxiv.org/abs/astro-ph/0408107), with the J2000 direction and proper-motion convention documented in the official Swiss programming documentation. The adopted factual reference direction is 17h45m40.03599s, −29°00′28.1699″; RA proper motion is stored as μRA cos Dec = −2.755718425 mas/yr, Dec −5.547 mas/yr. Distance is the explicitly assumed 8 kpc (0.125 mas parallax); radial velocity set to zero. These assumptions are not a fresh measurement.

## Precision and reference caveats

The HYG records are not substituted by Swiss star records. The independent result therefore has real catalogue and propagation differences. This is deliberate and visible in metadata. Linear Cartesian propagation includes tangential motion, radial motion, perspective change arising from that vector, annual parallax, and relativistic annual aberration. Solar gravitational deflection, binary orbits, light-time correction of a stellar catalogue epoch, and microarcsecond frame transformations are omitted. Galactic pole directions are geometric and do not receive annual aberration.

A numerical oracle is installed in the separately approved retained directory documented in `docs/ORACLE-ENVIRONMENT.md`. The user expressly asked that it remain available locally. It is not included in the Site. The fixture report distinguishes offset precision, matched-input geometric precision, common-TT physical ephemerides and each library's own UT-to-TT forecast. Finite sample agreement is not a full-domain certificate.

The independent fixture review found a sub-0.1″ inconsistency between the Liu preprint's Eq.23 printed matrix row and its Eq.22 sexagesimal pole. The implementation uses Eq.22. A separate test reconstructs Eq.22 from the original Eq.21 plane constraints and Eq.20 Galactic Center direction, agreeing to 2×10⁻¹⁰ in Cartesian components. The Eq.23 printed-row fixture keeps its own explicit looser tolerance and explanatory note; it is not used to alter the implemented pole.


Historical calibration formulas were implemented independently from [Kinoshita 1975, NASA-CR-142301, Table 4](https://ntrs.nasa.gov/api/citations/19750011026/downloads/19750011026.pdf) and the IAU1976 Euler angles reproduced in [Smith et al. 1989, Eq.15](https://adsabs.harvard.edu/pdf/1989AJ.....97..265S). The resulting fixed corrections are derived from frame rotations, not empirically fitted oracle constants.