sunholo/celestial
Pure celestial mechanics in float64: Kepler's equation (fixed 8-step Newton, residual < 1e-14 for e <= 0.97), position and velocity from Keplerian elements, Kepler's third law both ways (period, and the semi-major axis of a period, e.g. a synchronous orbit), the JPL Standish approximate planetary elements (Table 2a/2b, 3000 BC-3000 AD; outside it the secular terms freeze at the window edge and a mean-orbit flag is set), JPL satellite mean elements referred to a Laplace plane with apse and node precession, the Earth and Moon split out of the Earth-Moon barycentre with the DE440 mass ratio (Earth = EMB - mu r_geo, Moon = EMB + (1 - mu) r_geo), ecliptic J2000 to ICRS (obliquity 84381.406 arcsec) to galactic (Hipparcos 1997 matrix) rotations, and IAU WGCCRE 2015 pole and prime-meridian models. Light-travel (retarded) time by a fixed 4-step iteration, checked against JPL Horizons. Newtonian point-mass gravity in m/s^2 with IAU 2015 nominal GM, refusing inside a body, also relative to a body's centre for station-keeping. Lambert and Minnaert radiance and phase functions with rho tied to geometric albedo (rho = p(2k+1)/2) and Bond albedo (4 rho/(k+1)^2), and a body's illuminance at the observer from the star's illuminance at 1 AU passed as a parameter. Classical single-scattering ring layer (lit face, unlit face with its finite mu -> mu0 limit, transmission), ring bands and ring-shadow ray geometry. The ism module (0.4.0): real spherical harmonics l <= 2 and a star-shaped surface (the Local Interstellar Cloud of Linsky et al. 2019, refit to their Table 2 edge distances, median 0.378 pc), segment crossings by a 64-step bracket and 60 bisections, closed-form parameter intervals of a segment inside a cone shell, an ellipsoid or a slab, n_H from an A_V gradient (Bohlin 1978), HEALPix RING pixel centres (Gorski 2005; healpy-checked), an MRN plus big-grain-tail size distribution normalised to a dust mass density (Krueger et al. 2015 Ulysses data) with exact counts above a radius and an inverse-CDF sampler, and a Poisson draw from two uniforms. The stellar module (0.5.0): Claret & Bloemen 2011 V-band quadratic limb darkening (508 ATLAS and PHOENIX rows, bilinear, clamped and reported), log g from mass and radius, convection cell size and lifetime scaled from the Sun by the pressure scale height, granulation contrast as a temperature fluctuation, spot and facula temperatures, Howard et al. 1990 differential rotation, the solar cycle phase and Spoerer band, the Baumbach 1937 corona, and a line's observed wavelength under a Doppler factor. Units AU, days (TDB), km, radians, lux, cd/m^2 (ism: any one length unit, SI for grains). No dependency on any other package.
| Field | Value |
|---|---|
| Latest | 0.5.0 |
| Stability | experimental |
| Effects | IO |
| Exports | 10 modules |
| Last Updated | 2026-10-21T08:11:05Z |
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- sunholo/celestial/kepler
- sunholo/celestial/frames
- sunholo/celestial/ephemeris
- sunholo/celestial/lighttime
- sunholo/celestial/gravity
- sunholo/celestial/reflect
- sunholo/celestial/rings
- sunholo/celestial/ism
- sunholo/celestial/stellar
- sunholo/celestial/stellar_ld
No dependencies (pure standalone package).
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