## Changes Introduced in V7.0.0

The following describes the most significant changes which occurred in the AST library between versions V6.0-1 and V7.0.0:

1. Fundamental positional astronomy calculations are now performed using the IAU SOFA library where possible, and the Starlink PAL library SUN/268sun268 otherwise (the PAL library contains a subset of the Fortran Starlink SLALIB library re-written in C). Copies of these libraries are bundled with AST and so do not need to be obtained or built separately, although external copies of SOFA and PAL can be used if necessary by including the “–with-external_pal” option when configuring AST.