In view of increased interest in object-oriented systems for describing coordinate information, we present a description of the data model used by the Starlink AST library. AST provides a comprehensive range of facilities for attaching world co-ordinate systems to astronomical data, and for retrieving and interpreting that information in a variety of formats, including FITS-WCS. AST is a mature system that has been in use for more than 17 years, and may consequently be useful as a means of informing development of similar systems in the future.
@article{arxiv.1602.06681,
title = {AST: A library for modelling and manipulating coordinate systems},
author = {David Berry and Rodney Warren-Smith and Tim Jenness},
journal= {arXiv preprint arXiv:1602.06681},
year = {2016}
}