subject.hpp File Reference

Unified Subject type — one value to represent any celestial entity. More...

#include "altitude.hpp"
#include "azimuth.hpp"
#include "bodies.hpp"
#include "body_target.hpp"
#include "coordinates.hpp"
#include "ffi_core.hpp"
#include "target.hpp"
#include "time.hpp"
#include <vector>

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Classes
class	siderust::Subject
	Unified, lightweight handle representing any celestial subject. More...

Namespaces
namespace	siderust

Enumerations
enum class	siderust::SubjectKind : int32_t { siderust::Body = SIDERUST_SUBJECT_KIND_T_BODY , siderust::Star = SIDERUST_SUBJECT_KIND_T_STAR , siderust::Icrs = SIDERUST_SUBJECT_KIND_T_ICRS , siderust::GenericTarget = SIDERUST_SUBJECT_KIND_T_GENERIC_TARGET }
	Discriminant for the active field in a Subject. More...

Functions
qtty::Radian	siderust::altitude_at (const Subject &subj, const Geodetic &obs, const Time< TT, MJD > &mjd)
	Altitude at an instant (radians) for any subject.
std::vector< Period< TT, MJD > >	siderust::above_threshold (const Subject &subj, const Geodetic &obs, const Period< TT, MJD > &window, qtty::Degree threshold, const SearchOptions &opts={})
	Periods when a subject is above a threshold altitude.
std::vector< Period< TT, MJD > >	siderust::below_threshold (const Subject &subj, const Geodetic &obs, const Period< TT, MJD > &window, qtty::Degree threshold, const SearchOptions &opts={})
	Periods when a subject is below a threshold altitude.
std::vector< CrossingEvent >	siderust::crossings (const Subject &subj, const Geodetic &obs, const Period< TT, MJD > &window, qtty::Degree threshold, const SearchOptions &opts={})
	Threshold-crossing events for a subject.
std::vector< CulminationEvent >	siderust::culminations (const Subject &subj, const Geodetic &obs, const Period< TT, MJD > &window, const SearchOptions &opts={})
	Culmination (local extrema) events for a subject.
std::vector< Period< TT, MJD > >	siderust::altitude_ranges (const Subject &subj, const Geodetic &obs, const Period< TT, MJD > &window, qtty::Degree min_alt, qtty::Degree max_alt, const SearchOptions &opts={})
	Periods when a subject's altitude is within [min, max].
qtty::Degree	siderust::azimuth_at (const Subject &subj, const Geodetic &obs, const Time< TT, MJD > &mjd)
	Azimuth at an instant (degrees, N-clockwise) for any subject.
std::vector< AzimuthCrossingEvent >	siderust::azimuth_crossings (const Subject &subj, const Geodetic &obs, const Period< TT, MJD > &window, qtty::Degree bearing, const SearchOptions &opts={})
	Azimuth bearing-crossing events for a subject.
std::vector< AzimuthExtremum >	siderust::azimuth_extrema (const Subject &subj, const Geodetic &obs, const Period< TT, MJD > &window, const SearchOptions &opts={})
	Azimuth extrema (northernmost / southernmost) for a subject.
std::vector< Period< TT, MJD > >	siderust::in_azimuth_range (const Subject &subj, const Geodetic &obs, const Period< TT, MJD > &window, qtty::Degree min_deg, qtty::Degree max_deg, const SearchOptions &opts={})
	Periods when a subject's azimuth is within [min_deg, max_deg].

Detailed Description

Unified Subject type — one value to represent any celestial entity.

Subject is a lightweight tagged value (akin to std::variant) that wraps the FFI siderust_subject_t struct. It can carry:

Kind	Data
Body	siderust::Body discriminant
Star	borrows an existing siderust::Star
Icrs	inline spherical::Direction<frames::ICRS>
Target	borrows an existing DirectionTarget<…>

All unified functions (altitude_at, above_threshold, …) accept a Subject so the caller no longer needs separate sun::, moon::, body::, star::, icrs::, and target-specific calls.

Lifetime: when constructing from Star or DirectionTarget, the Subject borrows the handle — the original object must outlive it.

Example

using namespace siderust;
 
// From a solar-system body
Subject sun = Subject::body(Body::Sun);
qtty::Degree alt = altitude_at(sun, obs, now);
 
// From a catalog star
Star vega = Star::catalog("VEGA");
Subject s = Subject::star(vega);
auto periods = above_threshold(s, obs, window, qtty::Degree(10));
 
// From an ICRS direction
Subject d = Subject::icrs(spherical::Direction<frames::ICRS>(
    qtty::Degree(279.23), qtty::Degree(38.78)));

Definition in file subject.hpp.