Besselian 
This class implements Besselian coordinate systems.

Ecliptic 
An ecliptic coordinate system in a Julian frame.

Galactic 
The class defining Galactic coordinate system.

Helioecliptic 
A helioecliptic coordinate system at a given epoch.

ICRS 
A class defining the ICRS coordinate system.

Julian 
The class defining Julian coordinate systems.

PositionAngleConverter 
This class implements an algorithm that calculates the offsets between the
position angle expressed with respect to the poles in two different coordinate
systems.
