An AST Frame is an Object that is used to represent a coordinate system. Contrast this with a Mapping (), which is used to describe how to convert between coordinate systems. The two concepts are complementary and we will see how they work together in .
In this section we will discuss only basic Frames, which represent
Cartesian coordinate systems. More specialised types of Frame
(e.g. the SkyFrame, which represents celestial coordinate
systems, and the SpecFrame, which represents spectral coordinate
systems) are covered later ( and )
and, naturally, inherit the properties and behaviour of the simple Frames
AST A Library for Handling World Coordinate Systems in Astronomy