/* Calculate the apparent sidereal time at the meridian of Greenwich of a given date. * returns apparent sidereal time (degree). * Formula 11.1, 11.4 pg 83 */ double get_apparent_sidereal_time (double JD) { double correction, sidereal; struct ln_nutation nutation; /* get the mean sidereal time */ sidereal = get_mean_sidereal_time (JD); /* add corrections for nutation in longitude and for the true obliquity of the ecliptic */ get_nutation (JD, &nutation); /* GZ: This was the only place where this was used. I added the summation here. */ correction = (nutation.longitude * cos ((nutation.ecliptic+nutation.obliquity)*M_PI/180.)); sidereal += correction; return (sidereal); }
double get_mean_ecliptical_obliquity(double JDE) { struct ln_nutation nutation; get_nutation(JDE, &nutation); return nutation.ecliptic; }
double get_nutation_longitude(double JDE) { struct ln_nutation nutation; get_nutation(JDE, &nutation); return nutation.longitude; }