VISTA and Disk Files

Many VISTA commands read from or write to the disk, and therefore require filenames. The program has defined several default directories and extensions for the various types of files that VISTA uses: for example, images are stored in one directory, spectra in a second, procedures in a third, etc. Unless you specify otherwise, VISTA will automatically search in certain directories for images, spectra, etc., and will assume that the files have standard extensions. You can view these default directories with the VISTA command PRINT DIRECTORIES.

An example of a default directory is this: The WD command writes an image to disk with a filename specified in the command. Assume the default directory for images is /vista/ccd/ and the default file extension for images is .CCD. The command
\begin{example} \item[WD 2 m15\hfill]{} \end{example}
writes the image in buffer 2 to the file /vista/ccd/m15.fits You can override the default locations any time: for example

The default directories are established when the VISTA program is run by a subroutine called INITIAL. That subroutine has a standard list of directories and extensions that it loads into a common block for use by other subroutines. The default directories can be changed by the user in two ways:

  1. Use the SETDIR command from within VISTA

  2. Every user can set up his/her own set of default directories using environment variables. The appropriate environment variables to modify are:
    Variable Directory for
    V_CCDIR Images
    V_PRODIR Procedures
    V_SPECDIR Spectra
    V_FLUXDIR Flux calibrations
    V_LAMBDIR Wavelength calibrations
    V_COLORDIR TV color files
    V_DATADIR Data files.
    V_DAODIR DAOPHOT files.

    An example is: 

       setenv V\_CCDIR /demo/ccd/
    Remember, you must execute these setenv commands BEFORE starting VISTA.