ltpequ.c File Reference

#include "sofa.h"

Include dependency graph for ltpequ.c:

Functions
void	iauLtpequ (double epj, double veq[3])
	Long-term precession of the equator. Notes: More...

Function Documentation

iauLtpequ()

void iauLtpequ	(	double	epj,
		double	veq[3]
	)

Long-term precession of the equator. Notes:

1) The returned vector is with respect to the J2000.0 mean equator and equinox.

2) The Vondrak et al. (2011, 2012) 400 millennia precession model agrees with the IAU 2006 precession at J2000.0 and stays within 100 microarcseconds during the 20th and 21st centuries. It is accurate to a few arcseconds throughout the historical period, worsening to a few tenths of a degree at the end of the +/- 200,000 year time span.

Parameters

[in]	epj	Julian epoch (TT)
[out]	veq	equator pole unit vector