Subset of routines from the SLALIB library
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These 5 ForTran files, providing the SLALIB routine "refro", have been
included in the Gemini IRAF package by kind permission of their author,
Patrick Wallace of Tpoint Software. They are used by the GMOS task gfcube
to compensate for atmospheric dispersion when generating IFU datacubes.
Until v1.12beta of the Gemini IRAF package, the same routines were provided
by linking to IRAF's main copy of the SLALIB library, found under math$.
However, a reported change in the licensing of SLALIB (to the GNU General
Public License) within IRAF 2.16 would now prevent IRAF's copy from being
combined with another critical routine on which gfcube depends. In order to
continue building the Gemini package under IRAF 2.16+, we have therefore
reached an agreement to provide the included subset of SLALIB under a
different license, which allows for non-commercial use only. Please see the
conditions under which these files are distributed (the "Tpoint Software
License Agreement") in the header comments of each source file,
eg. refro.f.

Since these routines are more recent than IRAF's copies and contain a few
adjustments to numeric constants or coefficients, the resulting atmospheric
refraction adjustments may differ slightly from those derived using previous
versions of the Gemini IRAF package.

These source files have been slightly modified from the original material
copyrighted by TPS by renaming the routines for IRAF SPP compatibility,
exactly as in IRAF's SLALIB.

February 2013
