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Starlink SLALIB Library Available in IRAF V2.11 (1Dec95) (from CCS, NOAO Newsletter No. 44, December 1995) During the course of developing a set of WCS-based image registration tools for IRAF, it became clear that a set of accurate celestial coordinate transformation routines capable of supporting the equatorial (FK4, FK4-NO-E, FK5, and GAPPT), ecliptic, galactic, and supergalactic celestial coordinate systems was required. Although a subset of the required routines was available in various IRAF tasks and packages, a complete and consistent set was not. The required functionality (and much more), however, did exist in the Starlink Fortran SLALIB library. It would solve our problems if the library could be included in IRAF distributions. SLALIB is a library of routines intended to make accurate and reliable positional-astronomy applications easier to write. Most SLALIB routines are concerned with position and time, but a number of them have wider application for trigonometrical or numerical applications. SLALIB currently contains 164 routines covering the following topics: string decoding, sexagesimal conversions, angles, vectors and rotation matrices, calendars and timescales, precession and nutation, proper motion, FK4/5 and elliptic aberration, geocentric coordinates, apparent and observed place, azimuth and elevation, refraction and airmass, ecliptic, galactic, and supergalactic coordinates, ephemerides, astrometry, and numerical methods. SLALIB is written in Fortran 77 and currently runs independently under VAX/VMS, Unix, and several PC platforms (a C version is also available). The Starlink project has agreed to permit IRAF to include SLALIB in future releases of IRAF. Beginning with IRAF V2.11, the SLALIB routines will be available in the IRAF core system math libraries, where they will be available for use in all IRAF software. Prior to the release of IRAF V2.11, the SLALIB routines may be included as part of any external packages currently under development which require them. We feel that these routines are potentially useful in many astronomical applications and hope that IRAF programmers will make good use of them. Lindsey Davis, Patrick Wallace
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