libnova  v 0.16.0
Proper Motion


void LIBNOVA_EXPORT ln_get_equ_pm (struct ln_equ_posn *mean_position, struct ln_equ_posn *proper_motion, double JD, struct ln_equ_posn *position)
 Calculate a stars equatorial position wrt proper motion (J2000). More...

Detailed Description

Proper motion is the motion in space of a star between 2 epochs. It has components in right ascension and in declination.

All angles are expressed in degrees.

Function Documentation

void ln_get_equ_pm ( struct ln_equ_posn mean_position,
struct ln_equ_posn proper_motion,
double  JD,
struct ln_equ_posn position 

Calculate a stars equatorial position wrt proper motion (J2000).

mean_positionMean position of object.
proper_motionAnnual Proper motion of object.
JDJulian Day.
positionPointer to store new object position.

Calculate a stars equatorial coordinates from it's mean coordinates (J2000.0) with the effects of proper motion for a given Julian Day.

Referenced by ln_get_apparent_posn().