1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
// SPDX-License-Identifier: AGPL-3.0-only
// Copyright (C) 2026 Vallés Puig, Ramon
//! # Generic celestial-body surface observers
//!
//! ## Scientific scope
//!
//! A surface observer is a point fixed relative to a celestial body's
//! reference surface and body-fixed frame. Geometric altitude and azimuth
//! are measured in the local east–north–up (ENU) system at that site:
//! altitude above the local geometric horizon (zenith = +90°) and azimuth
//! from north through east (0° = north, 90° = east).
//!
//! This module provides body-agnostic surface geometry for any body that
//! implements [`BodySurfaceModel`] with a documented reference surface and
//! body-fixed orientation. Earth, the Moon, Mars, Mercury, Venus, and Pluto
//! are provided. Gas giants do not implement the trait unless a mission
//! supplies an explicit reference surface (e.g. a 1-bar level).
//!
//! **Longitude** is always stored east-positive. This matches planetocentric /
//! body-fixed Cartesian conventions. External **planetographic** longitudes
//! may use a different sense (west-positive for Mars in NAIF SPICE); convert
//! explicitly with [`east_positive_from_planetographic`] or
//! [`BodySurfaceModel::east_positive_longitude`]. No hidden sign flips occur
//! inside constructors. Latitude uses [`LatitudeConvention`] independently.
//!
//! Negative heights are permitted until the inward reference-surface normal
//! reaches a curvature/centre singularity; invalid interior sites are rejected
//! during construction or deserialization. Cartesian Horizontal axes follow
//! affn's spherical convention: +X north, +Y east and +Z local up. At exact
//! zenith/nadir, azimuth is set to 0 by convention because it is physically
//! undefined.
//!
//! Lunar fixed orientation uses the NAIF `IAU_MOON` analytical Mean-Earth
//! model with 13 periodic arguments ([`crate::coordinates::frames::MoonIauMeanEarth`]),
//! **not** a DE-specific `MOON_PA` / binary-PCK `MOON_ME` realisation. The
//! legacy name `MoonPrincipalAxes` is a compatibility alias for the same
//! marker. Public epochs are TT; tempoch converts them to TDB for lunar
//! orientation.
//!
//! Geometric Alt/Az computed here does **not** include atmospheric
//! refraction, aberration, light deflection, light-time, or terrain
//! occultation. Those belong in the observation / event pipelines.
//!
//! ## Technical scope
//!
//! - [`ReferenceSurface`] — spherical or ellipsoidal reference surface
//! - [`LatitudeConvention`] — planetocentric vs planetographic latitude
//! - [`PlanetographicLongitudeSense`] — external planetographic longitude sense
//! - [`BodySurfaceModel`] — compile-time link of body → center, fixed frame,
//! and default surface
//! - [`SurfaceSite`] — typed observer site on body `B` (e.g. `SurfaceSite::<Moon>`)
//! - [`SurfaceObserver`] — parameterized reference center carrying site params
//! - Local ENU basis and body-fixed Cartesian conversion
//!
//! Horizontal transforms live in
//! [`crate::coordinates::transform::surface_horizontal`].
//!
//! ## References
//!
//! - IAU Working Group on Cartographic Coordinates and Rotational Elements
//! (2015). *Celestial Mechanics and Dynamical Astronomy* 130, 22.
//! - Archinal et al. (2018). Report of the IAU WGCCRE. *Celestial Mechanics
//! and Dynamical Astronomy* 130, 22.
//! - NAIF, `pck00011.tpc`, IAU_MOON analytical Mean-Earth orientation;
//! planetographic longitude sense via SPICE `pgrrec` / `plnsns`.
//! - See also [`crate::coordinates::transform::horizontal`] for the
//! Earth-specific GAST path retained for backward compatibility.
pub use ;
pub use ;
pub use ;
pub use SurfaceError;
pub use ReferenceSurface;
pub use SurfaceSite;