Sky_TrueEquatorial Struct Reference

Struct used for holding an object's coordinates in equatorial apparent or Intermediate coordinates. More...

Data Fields
double	timestamp_cy
	Time applying to the other figures in this struct (centuries since J2000.0, TT timescale)
V3D_Vector	appCirsV
	Direction of object in apparent or CIRS coordinates (effectively a unit vector).
double	distance_au
	Distance to object (Astronomical Units) or 0.0 for far distant objects (that is, those with negligible diurnal parallax)
double	eqEq_rad
	Equation of the Equinoxes (radian).

Detailed Description

Struct used for holding an object's coordinates in equatorial apparent or Intermediate coordinates.

Apparent coordinates are those referred to the true equator and equinox of the time indicated in field timestamp_cy. Intermediate coordinates are in the Celestial Intermediate Reference System (CIRS), referred to the true equator of time timestamp_cy and to the Celestial Intermediate Origin (CIO) instead of the equinox. If the object is in Apparent coordinates, the Equation of the Equinoxes (eqEq_rad) field is required as part of converting to topocentric coordinates. If the object is in CIRS coordinates, field eqEq_rad can be ignored.

This structure is returned by the sun_nrelApparent(), moon_nrelApparent(), (future)planet_getApparent() and (future)star_getApparent() functions, and importantly for tracking, the skyfast_getApprox() function.

Examples

demo4_multiple_sites.c.

Definition at line 106 of file sky.h.

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The documentation for this struct was generated from the following file:

• sky.h