longTermEclipticPole function

Vector3 longTermEclipticPole(
  1. double t
)

Pole of the mean ecliptic of date at t (Julian centuries TT since J2000) as a unit vector in the J2000 mean equator and equinox frame; long-term model valid for ±200 000 years (Vondrák, Capitaine and Wallace 2011).

Implementation

Vector3 longTermEclipticPole(double t) {
  final (p, q) = longTermEclipticPoleAngles(t);
  final z = math.sqrt(math.max(1 - p * p - q * q, 0));
  final s = math.sin(_epsilon0), c = math.cos(_epsilon0);
  return Vector3(p, -q * c - z * s, -q * s + z * c);
}