astroceleste-engine
Copyright (c) 2026 The astroceleste-engine contributors
Licensed under MIT OR Apache-2.0.

This software ports algorithms and data from Skyfield
(https://github.com/skyfielders/python-skyfield), used under the MIT license:

    Copyright © 2013–2018 Brandon Rhodes

    Permission is hereby granted, free of charge, to any person obtaining a copy of this
    software and associated documentation files (the "Software"), to deal in the Software
    without restriction, including without limitation the rights to use, copy, modify,
    merge, publish, distribute, sublicense, and/or sell copies of the Software, and to
    permit persons to whom the Software is furnished to do so, subject to the following
    conditions:

    The above copyright notice and this permission notice shall be included in all copies
    or substantial portions of the Software.

    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
    INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
    PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
    HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
    CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE
    OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Ported parts: the ΔT model and its tables (src/time.rs, src/data/deltat.bin), IAU 2000A
nutation and its coefficient tables (src/frames/nutation*.rs), IAU 2006 precession, frame
bias and sidereal time (src/frames/), light-time, gravitational deflection and aberration
(src/ephemeris/observe.rs).

Ephemeris data: NASA JPL planetary ephemerides (DE440s and others) are public domain
works of the U.S. Government, fetched at build/run time and not distributed here, except
for a one-year DE440s excerpt used by the tests (tests/data/de440s_2000.bsp).
