EclToEq converts ecliptic coordinates to equatorial coordinates.

EqToEcl converts equatorial coordinates to ecliptic coordinates.

EqToGal converts equatorial coordinates to galactic coordinates.

EqToHz computes Horizontal coordinates from equatorial coordinates.

GalToEq converts galactic coordinates to equatorial coordinates.

HzToEq transforms horizontal coordinates to equatorial coordinates.

NewObliquity constructs a new Obliquity.

Meeus gives 33 as the origin of galactic longitudes relative to the ascending node of of the galactic equator.

IAU B1950.0 coordinates of galactic North Pole.

Ecliptic coordinates are referenced to the plane of the ecliptic.

Equatorial coordinates are referenced to the Earth's rotational axis.

Galactic coordinates are referenced to the plane of the Milky Way.

Horizontal coordinates are referenced to the local horizon of an observer on the surface of the Earth.

Obliquity represents the obliquity of the ecliptic.