greenwichMeanSiderealTimeIau2006 function

double greenwichMeanSiderealTimeIau2006(
  1. double jdUt,
  2. double jdTT
)

Greenwich mean sidereal time (radians, 0 ≤ GMST < 2π), IERS Conventions (2010), table 5.2e: θ plus the IAU 2006 precession polynomial in time jdTT. Accurate only within about ±1000 years of J2000.

Implementation

double greenwichMeanSiderealTimeIau2006(double jdUt, double jdTT) {
  final t = centuriesSinceJ2000(jdTT);
  final polynomial =
      (0.014506 +
          t *
              (4612.156534 +
                  t *
                      (1.3915817 +
                          t *
                              (-0.00000044 +
                                  t * (-0.000029956 + t * -0.0000000368))))) *
      arcsecond;
  return (earthRotationAngle(jdUt) + polynomial) % (2 * math.pi);
}