gmst property

Angle gmst

Calculate Greenwich Mean Sidereal Time for the Julian date.

Returns the angle, in radians, measuring eastward from the Vernal Equinox to the prime meridian. This angle is also referred to as "ThetaG" (Theta GMST).

Implementation

Angle get gmst {
  final jdut1 = value;

  var tut1 = (jdut1 - 2451545.0) / 36525.0;
  var temp = -6.2e-6 * tut1 * tut1 * tut1 +
      0.093104 * tut1 * tut1 +
      (876600.0 * 3600 + 8640184.812866) * tut1 +
      67310.54841; // # sec
  temp =
      temp * _deg2rad / 240.0 % _twopi; // 360/86400 = 1/240, to deg, to rad

  //  ------------------------ check quadrants ---------------------
  if (temp < 0.0) {
    temp += _twopi;
  }
  return Angle.radian(temp);
}