==============================================================================
references.txt  —  ephemeris migration source list
Project (c) 2026 Elizabeth Huston, Ph.D. and Noah Christian, Ph.D. — MIT (see LICENSE).
Contact: elpisastrology@gmail.com · elpisastrology.com and noahchristian@gmail.com
Compiled 2026-07 during the swisseph-replacement research.
Not legal advice. Where an obligation is load-bearing for the business, have
counsel read the actual license text against the actual deployment.
==============================================================================

Legend:
  [SHIP]  = code/data that would ship in the product -> obligation attaches
  [GEN]   = used only offline to GENERATE fixtures -> no shipping obligation
  PD      = public domain / not copyrightable


==============================================================================
TIER 1 — NEEDED FOR ATTRIBUTION OR LICENSING
(Anything whose code or data the project uses. Obligations attach; comply.)
==============================================================================

1. Swiss Ephemeris / pyswisseph  [GEN only — MUST NOT SHIP]
   https://www.astro.com/swisseph/
   https://github.com/astrorigin/pyswisseph
   License: AGPL-3.0 OR Astrodienst Professional License (dual).
   Obligation: AGPL sec.13 forces full app source disclosure to network users.
     We use it ONLY offline to emit reference numbers (facts). Do NOT link it
     into the shipped web app and do NOT vendor its source or .se1 files.
     If it ever ships, you owe either AGPL source disclosure OR a paid license.

2. Skyfield  [SHIP]
   https://github.com/skyfielders/python-skyfield   (license: MIT — confirmed)
   https://rhodesmill.org/skyfield/
   Obligation: MIT — retain the copyright + permission notice in your distribution
     (e.g. a THIRD-PARTY-NOTICES file). No copyleft. Safe to ship commercially.

3. JPL Horizons / JPL Solar System Dynamics — ephemerides & small-body SPK kernels
   [SHIP data — for Chiron / asteroids]
   https://ssd.jpl.nasa.gov/horizons/            (system)
   https://ssd.jpl.nasa.gov/horizons/manual.html (SPK .bsp generation — confirmed)
   https://ssd.jpl.nasa.gov/sb/orbits.html       (small-body orbits)
   Status: US Government work -> not copyrightable (17 U.S.C. sec.105), effectively PD.
   Obligation: none legally required for the DATA. Acknowledgment of JPL/NASA is
     requested/courteous. (See Tier 2 note re: NASA "commercial" caveats = imagery,
     not data.)

4. Hipparcos catalog (ESA)  [SHIP data — for fixed stars, default path]
   Loaded by Skyfield via CDS mirror (hip_main.dat).
   https://www.cosmos.esa.int/web/hipparcos
   Status: ESA astrometric data, freely usable.
   Obligation: acknowledgment of ESA/Hipparcos requested. Coordinates themselves
     are facts (not copyrightable) — freezing per-star values in-repo removes the
     file dependency entirely (see fixed_stars.py INLINE_COORDS).

5. Yale Bright Star Catalogue (BSC5)  [SHIP data — optional fixed-star source]
   http://tdc-www.harvard.edu/catalogs/bsc5.html
   Status: long-standing, openly redistributed, treated as public/free.
   Obligation: acknowledgment courteous; verify the specific mirror's notice.

6. Moshier ephemeris  [SHIP — candidate engine for Sun..Pluto + nodes + Lilith]
   http://www.moshier.net/   (Steve Moshier's astronomical code)
   Status: PUBLIC DOMAIN. (Same model swisseph uses in its data-file-free mode.)
   Obligation: none. Attribution courteous.

7. pandas  [SHIP — Skyfield dependency for Hipparcos loading]
   https://pandas.pydata.org/   License: BSD-3-Clause.
   Obligation: retain BSD notice.

8. IANA Time Zone Database (via tzdata / stdlib zoneinfo)  [SHIP]
   https://www.iana.org/time-zones
   Status: public domain. Obligation: none. Powers DST / historical / LMT offsets.

9. timezonefinder  [SHIP]
   https://github.com/jannikmi/timezonefinder   (code: MIT)
   Bundled timezone-boundary polygons derived from OpenStreetMap -> ODbL
   (share-alike on the DATA). Obligation: attribute "(c) OpenStreetMap
   contributors (ODbL)". Code itself is MIT.

10. geopy + geocoder backends  [SHIP connector; data per backend]
   https://github.com/geopy/geopy   (code: MIT)
   * Nominatim / OpenStreetMap (default): data ODbL -> attribute "(c) OpenStreetMap
     contributors"; USAGE POLICY: <=1 req/s, valid user_agent, no bulk/heavy use.
   * Google Maps Geocoding (optional): commercial ToS + API key; caching/display
     restrictions apply -- read Google's terms before production use.

CAUTION (belongs conceptually in Tier 1 — a licensing TRAP):
 *  HYG database (Hipparcos+Yale+Gliese+Gaia DR3)
    https://codeberg.org/astronexus/hyg   License: CC-BY-SA 4.0.
    SHARE-ALIKE. Convenient bundle, but its copyleft attaches to the data file.
    Prefer raw Hipparcos/Yale/JPL (or frozen facts) to avoid share-alike.
 *  Kerykeion / flatlib (astrology libs) — wrap pyswisseph -> inherit AGPL.
    Do NOT adopt as a "permissive" shortcut. https://kerykeion.net/


==============================================================================
TIER 2 — GOOD TO REFERENCE, NOT NECESSARY (with caveats)
(Authoritative-enough for understanding; not a license basis to rely on.)
==============================================================================

*  NASA — images & media usage / copyright status
   https://www.nasa.gov/nasa-brand-center/images-and-media/
   CAVEAT: This page governs IMAGERY, logos, and endorsement — NOT raw ephemeris
   data. Its "commercial uses have stricter requirements" language is about
   photos/branding/identifiable people. Use of NASA/JPL DATA does not imply NASA
   endorsement, and ephemeris numbers are PD under 17 U.S.C. sec.105. Don't
   over-read this page as restricting the Chiron data.

*  JPL Horizons manual — SPK file production details (Tier 1 item #3's manual).
   Reference for HOW to generate the Chiron .bsp; no license terms stated on it.

*  Skyfield documentation (technical reference; obligation is just the MIT notice)
   https://rhodesmill.org/skyfield/stars.html          (Star class, Hipparcos, ecliptic epoch)
   https://rhodesmill.org/skyfield/positions.html
   https://rhodesmill.org/skyfield/kepler-orbits.html  (minor-planet via MPC elements)
   https://rhodesmill.org/skyfield/api-ephemeris.html  (SPK/.bsp loading)
   https://rhodesmill.org/skyfield/planets.html

*  Minor Planet Center — MPCORB.DAT / CometEls.txt (alt. Chiron/asteroid source)
   CAVEAT: licensing historically murkier than JPL. Prefer JPL SPK kernels.

*  Wikipedia — background only, NOT a licensing authority
   https://en.wikipedia.org/wiki/2060_Chiron
   https://en.wikipedia.org/wiki/Bright_Star_Catalogue
   https://en.wikipedia.org/wiki/JPL_Horizons_On-Line_Ephemeris_System
   https://en.wikipedia.org/wiki/JPL_Small-Body_Database
   CAVEAT: fine for orbital facts / HIP numbers; do not cite as legal basis.


==============================================================================
TIER 3 — SEARCH DETRITUS (pulled a fact here or there; nothing load-bearing)
(Recorded for provenance; none of these should be relied on or cited.)
==============================================================================

Black Moon Lilith vs asteroid 1181 (lay confirmation of the distinction only):
   https://darkstarastrology.com/three-liliths/           (used: 3-Lilith distinction)
   https://astrolibrary.org/interpretations/lilith/
   https://www.astrologyanswers.com/article/four-liliths-birth-chart/
   https://theinnerwheel.com/black-moon-lilith-astrology-guide/
   https://www.augurine.com/learn/lilith
   https://lilithcalculator.com/blog/what-is-black-moon-lilith/
   https://blessedbemagick.com/blogs/news/lilith-is-in-our-astrological-lives
   https://kerykeion.net/content/learn-astrology/foundation-lilith-variants
   https://www.tumblr.com/lunarticxenia/664273304460410880/
   https://jp.tradingview.com/script/U2ZIpSzu-Financial-Astrology-Mean-Lilith-Black-Moon-Longitude

Star-catalog / misc results that surfaced but weren't used substantively:
   https://www.astronexus.com/projects/hyg
   https://www.projectrho.com/public_html/starmaps/catalogues.php
   https://ian.macky.net/pat/yalebsc/index.html
   https://grokipedia.com/page/Bright_Star_Catalogue
   https://svs.gsfc.nasa.gov/4851                          (Deep Star Maps 2020)
   https://www.researchgate.net/publication/361786663_USNO_Bright_Star_Catalog_Version_1
   https://en.wikipedia.org/wiki/Hipparchus_star_catalog   (the ANCIENT catalog — irrelevant)
   https://en.wikipedia.org/wiki/57424_Caelumnoctu
   https://planetmapper.readthedocs.io/en/stable/spice_kernels.html
   https://mycoding.uk/a/ephemerides.html
   https://www.wikidata.org/wiki/Q15611                    (2060 Chiron wikidata)
   https://catalog.data.gov/dataset/horizons
   https://github.com/skyfielders/python-skyfield/discussions/1034


==============================================================================
ATTRIBUTION SNIPPET TO SHIP (if/when a permissive engine goes live)
Put in a THIRD-PARTY-NOTICES / CREDITS file:
------------------------------------------------------------------------------
  This product computes astronomical positions using Skyfield (MIT License,
  (c) Brandon Rhodes) and pandas (BSD). Planetary positions use the
  public-domain Moshier ephemeris. Minor-body (e.g. Chiron) positions derive
  from JPL Horizons / NASA-JPL data (public domain). Fixed-star astrometry
  derives from the ESA Hipparcos catalogue. This product is not endorsed by
  or affiliated with NASA, JPL, or ESA.
  [If pyswisseph is EVER linked in: add AGPL source offer OR cite the
   Astrodienst Professional License number.]
==============================================================================
