gcrsToEclipticOfDate function

Vector3 gcrsToEclipticOfDate(
  1. Vector3 r,
  2. double t, {
  3. required double nutationInLongitude,
})

Transforms vector r from the GCRS (ICRF) to the ecliptic and equinox of date.

With nutationInLongitude equal to Δψ the result refers to the true equinox of date (as in a horoscope); with zero – to the mean equinox.

Precession from the long-term model (Vondrák, Capitaine and Wallace 2011), valid for ±200 000 years; nutation in longitude is a rotation about the pole of the ecliptic of date.

Implementation

Vector3 gcrsToEclipticOfDate(
  Vector3 r,
  double t, {
  required double nutationInLongitude,
}) => longTermGcrsToMeanEclipticOfDate(r, t).rotateZ(-nutationInLongitude);