Function icrsToEcl( xyz )

Description:
Converts a 3-element vector representing ICRS (equatorial) coordinates to ecliptic coordinates. This can be used with position or velocity vectors.

The transformation corresponds to that between the coordinates (ra,dec) and (ecl_lon,ecl_lat) in the Gaia source catalogue (DR2).

Parameters:
xyz (array of floating point)
3-element vector giving ICRS Cartesian components
Return Value (array of floating point):
3-element vector giving ecliptic Cartesian components
Example:
icrsToEcl(polarXYZ(ra, dec, distance))
Signature:
double[] icrsToEcl(double[])