Nutation

Functions
void LIBNOVA_EXPORT	ln_get_nutation (double JD, struct ln_nutation *nutation)
	Calculate nutation. More...
void LIBNOVA_EXPORT	ln_get_equ_nut (struct ln_equ_posn *mean_position, double JD, struct ln_equ_posn *position)
	Calculate equatorial coordinates with the effects of nutation. More...

Detailed Description

Nutation is a period oscillation of the Earths rotational axis around it's mean position.

All angles are expressed in degrees.

Function Documentation

ln_get_equ_nut()

void ln_get_equ_nut	(	struct ln_equ_posn *	mean_position,
		double	JD,
		struct ln_equ_posn *	position
	)

Calculate equatorial coordinates with the effects of nutation.

Parameters

mean_position	Mean position of object
JD	Julian Day.
position	Pointer to store new object position.

Calculate a stars equatorial coordinates from it's mean equatorial coordinates with the effects of nutation for a given Julian Day.

References ln_equ_posn::dec, ln_nutation::ecliptic, ln_deg_to_rad(), ln_get_nutation(), ln_nutation::longitude, ln_nutation::obliquity, and ln_equ_posn::ra.

Referenced by ln_get_apparent_posn().

ln_get_nutation()

void ln_get_nutation	(	double	JD,
		struct ln_nutation *	nutation
	)

Calculate nutation.

Parameters

JD	Julian Day.
nutation	Pointer to store nutation

Calculate nutation of longitude and obliquity in degrees from Julian Ephemeris Day

References ln_nutation::ecliptic, ln_deg_to_rad(), ln_get_jde(), ln_nutation::longitude, and ln_nutation::obliquity.

Referenced by ln_get_apparent_sidereal_time(), ln_get_ecl_from_equ(), ln_get_equ_from_ecl(), ln_get_equ_nut(), ln_get_heliocentric_time_diff(), ln_get_solar_ecl_coords(), and ln_get_solar_equ_coords().