UT2 top-level property

TimeInstantUnits UT2

Universal Time (UT2): UT2 = UT1 + 0.022 sin(2PIt) - 0.012 cos(2PIt) - 0.006 sin(4PIt) + 0.007 cos(4PIt), where t = the date in Besellian years

Implementation

// ignore: non_constant_identifier_names
final TimeInstantUnits UT2 = TimeInstantUnits('Universal Time (UT2)', 'UT2',
    'UT2', 'Universal Time (UT2)', 1.0, false, 0.0, (dynamic val) {
  //double d = val is num ? val.toDouble() : val is Number ? val.toDouble() : 0.0;
  final d = UT1.fromMks(val); // UT1
  const twoPI = 2.0 * pi;
  const fourPI = 2.0 * twoPI;
  final t = B.fromMks(UT1.toMks(d)).toDouble();
  return d +
      (0.022 * sin(twoPI * t) -
          0.012 * cos(twoPI * t) -
          0.006 * sin(fourPI * t) +
          0.007 * cos(fourPI * t));
}, (dynamic val) {
  var d = val is num
      ? val.toDouble()
      : val is Number
          ? val.toDouble()
          : 0.0;
  const twoPI = 2.0 * pi;
  const fourPI = 2.0 * twoPI;
  final t = B
      .fromMks(UT1.toMks(d))
      .toDouble(); // besselian -- use UT2 value as UT1... close enough
  d -= 0.022 * sin(twoPI * t) -
      0.012 * cos(twoPI * t) -
      0.006 * sin(fourPI * t) +
      0.007 * cos(fourPI * t); // UT1

  return UT1.toMks(d);
});