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{\LARGE \bf Synphot Data Installation Guide}
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\section{Setting the Top Directory}

The synphot tasks assume that all the synphot reference files are
stored under a single top level directory. This directory is referred
to inside STSDAS by the logical name {\tt crrefer}. This directory
may be anywhere you have sufficient space to install the reference
files (approximately 400 megabytes is required for the full
installation), but we recommend that it not be placed as subdirectory
of the STSDAS or TABLES source code. This will make it easier to
update STSDAS without needing to reinstall the Synphot data. Once the
top directory is created, the environment variable {\tt crrefer}
should be set in your {\tt extern.pkg} file. This file can be found in
{\tt \$iraf/unix/hlib} on Unix systems.
To set {\tt crrefer} add a command similar to the following
to the file:

\begin{quote}\begin{verbatim}
set crrefer = "/your/path/name/to/refer/"
\end{verbatim}\end{quote}

\section{Unpacking the Data Sets}

The Synphot data should be downloaded from our web server at:

\begin{quote}\begin{verbatim}
http://www.stsci.edu/resources/software_hardware/stsdas/synphot
\end{verbatim}\end{quote}

There are four compressed tar files containing the data and this
installation guide. The first tar file contains the Synphot component
throughput tables, the second contains various observed and modelled
spectral coatalogs, the third contains the 1993 Kurucz model stellar
spectra, and the fourth contains the HST calibration standard
spectra.

First, place the compressed tar files in the top level directory you
created in the first section. Then, uncompress and untar the tar
files. On a Unix system, the following commands will accomplish this.

\begin{quote}\begin{verbatim}

% gunzip synphot1.tar.gz
% tar -xvf synphot1.tar

% gunzip synphot2.tar.Z 
% tar -xvf synphot2.tar

% gunzip synphot3.tar.Z 
% tar -xvf synphot3.tar

% gunzip synphot4.tar.Z 
% tar -xvf synphot4.tar

\end{verbatim}\end{quote}

The tar file synphotpsf.tar.Z contains the psf images used with the
simulators package of synphot. If you are not planning to use this
package, you do not need to install it. The tar file should be copied
to the {\tt scidata} directory of stsdas, uncompressed, and untarred.


Type the following commands when in stsdas:

\begin{quote}\begin{verbatim}

cl> copy /your/path/to/synphotpsf.tar.Z scidata$
cl> cd scidata$
cl> !uncompress synphotpsf.tar.Z
cl> rtar -xvf synphotpsf.tar

\end{verbatim}\end{quote}

\section{Updating the Synphot Parameter File}

We have converted all the Synphot files to FITS format. For the most
part, this change is transparent to you, but in order to have Synphot
use the new files, you must edit the {\tt refdata} parameter set. The
new parameter set should have the values:

\begin{quote}\begin{verbatim}
area = 45238.93416 (unchanged)
grtbl = mtab$*_tmg.fits
cmptbl = mtab$*_tmc.fits
\end{verbatim}\end{quote}

Each user can edit the parameter set with the command {\tt epar
refdata} in Iraf. Or, to make the change for all users on the system,
modify the file {\tt synphot\$refdata.par} with a text editor. (The
name is an iraf logical. You can see the name on your system by
loading the {\tt synphot} and {\tt hst\_calib} packages in iraf and
typing ``{\tt path synphot\$refdata.par}''.)

\section{When Disaster Strikes}

If you encounter problems installing the Synphot data files, we
encourage you to contact us via the STSDAS help desk {\tt
help@stsci.edu}.  If you are unable to use this mechanism, please call
the help desk at 1-800-544-8125 or (410) 338--1082 or write us at

\begin{quote}
Scientific Software Group\\
Science Support Division\\
Space Telescope Science Institute\\
3700 San Martin Drive\\
Baltimore, MD 21218
\end{quote}

If you have any suggestions for improvement in either the installation
procedure or this gude, please feel free to contact us.

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