Purpose

SLALIB¹is a library of routines intended to make accurate and reliable positional-astronomy applications easier to write. Most SLALIB routines are concerned with astronomical position and time, but a number have wider trigonometrical, numerical or general applications. The applications ASTROM, COCO, RV and TPOINT all make extensive use of the SLALIB routines, as do a number of telescope control systems around the world. The SLALIB versions currently in service are written in Fortran 77 and run on VAX/VMS, several Unix platforms and PC. A proprietary ANSI C version is also available from the author; it is functionally similar to the Fortran version upon which the present document concentrates.